Lab-tested storage, starting with memory cards

CKBench is the bench we built because the numbers on the package answer almost none of the questions that matter. Every test byte is committed to the device and confirmed, every byte is read back and checked, and the result gets published whether it flatters the product or not. Its first module is CardCheck, for memory cards, and a microSD is a good place to start: it is the cheapest component in your dash cam and the one most likely to quietly ruin it.

CardCheck · the corpus

Memory cards: every one we have tested

Same bench, same reader, same suite, with one exception the table states outright: a microSD Express card carries PCIe on its second row of pins and cannot reach that bus through any ordinary reader, so it was run on both and appears twice, once per bus. Every other row shares one measurement chain. Write speed is committed sequential, which reads lower than burst benchmarks because every byte had to land before the clock stopped. Capacity is what the card actually delivered against the number on its label, verified byte by byte.

Card	Committed write	Sustained floor	Capacity delivered	Peak temp	Score
SanDisk High Endurance 128GB	89.7 MB/s	88.0 MB/s, V60	100.0% of label	151.4 F	5/5
Kioxia Exceria G2 128GB	65.3 MB/s	62.6 MB/s, V60	96.7% of label	143.3 F	4.5/5
VIOFO High Endurance 128GB	57.0 MB/s	55.8 MB/s, V30	97.4% of label	160.8 F	3.5/5
VIOFO High Endurance 32GB	35.3 MB/s	34.3 MB/s, V30	99.1% of label	153.0 F	4/5
ProGrade SDXC UHS-II V60 128GB	108.4 MB/s	102.8 MB/s, V90	100.1% of label	145.1 F	4/5
Lexar Professional 1667x 128GB	119.3 MB/s	109.5 MB/s, V90	100.0% of label	142.7 F	4.5/5
Samsung PRO Ultimate SD 512GB	137.3 MB/s	133.1 MB/s, V90 on this reader V60 in a camera	100.1% of label	144.4 F	4.5/5
Samsung P9 Express 256GB (SD Express)	212.9 MB/s	161.3 MB/s, V90	100.1% of label	194.8 F	4/5
Samsung P9 Express 256GB (UHS-I fallback)	87.7 MB/s	87.0 MB/s, V60	100.1% of label	140.9 F	4/5
Samsung PRO Plus 512GB	142.2 MB/s	141.6 MB/s, V90	100.1% of label	169.6 F	4.5/5
Botslab 128GB (bundled)	59.0 MB/s	53.9 MB/s, V30	97.4% of label	135 F	4.5/5
FitcamX 64GB (bundled)	47.1 MB/s	43.8 MB/s, V30	97.3% of label	131 F	4/5
Newegg TeamGroup 128GB	39.8 MB/s	35.5 MB/s, V30	96.7% of label	133 F	3.5/5
SanDisk ImageMate 128GB	33.2 MB/s	31.8 MB/s, V30	26.8% of label	150.1 F	1/5
SanDisk Extreme 512GB	135.8 MB/s	127.6 MB/s, V90	100.0% of label	172.3 F	4.5/5
Lexar Silver Plus 128GB	182.7 MB/s	187.3 MB/s, V90	98.8% of label	158.0 F	4.5/5
Samsung EVO Plus 128GB	82.0 MB/s	83.6 MB/s, V60	100.0% of label	135.0 F	5/5
SanDisk Ultra 128GB	60.7 MB/s	59.7 MB/s, V30	99.9% of label	155.0 F	4.5/5
Lexar Blue 128GB	152.6 MB/s	155.1 MB/s, V90	98.2% of label	162.0 F	4.5/5
Generic PRO PLUS 128GB	12.5 MB/s	11.9 MB/s, V10	51.9% of label	110 F	1/5
Generic MICRODRIVE 128GB	13.8 MB/s	12.8 MB/s, V10	37.5% of label	118 F	1/5
Generic LD 128GB	15.5 MB/s	14.6 MB/s, V10	50.7% of label	111 F	1/5
Vantrue Endurance PRO 128GB	84.7 MB/s	83.4 MB/s, V60	98.8% of label	170 F	4.5/5
SanDisk High Endurance 512GB	135.0 MB/s	68.0 MB/s, V60	100.0% of label	174 F	4/5
VIOFO High Endurance 64GB	61.2 MB/s	59.5 MB/s, V30	97.4% of label	174.4 F	4/5
Gigastone High Endurance Pro 128GB	58.5 MB/s	31.0 MB/s, V30 59.6 fresh	97.7% of label	132 F	4.5/5
Amazon Basics 128GB	189.4 MB/s	188.1 MB/s, V90	98.2% of label	171 F	4.5/5
PNY Premier-X 128GB	53.6 MB/s	47.1 MB/s, V30	97.7% of label	129 F	4.5/5
Silicon Power Superior Pro 128GB	85.4 MB/s	37.8 MB/s, V30	97.2% of label	123.7 F	4/5
Metorage Industrial 64GB	60.5 MB/s	59.6 MB/s, V30	97.4% of label	172.1 F	4/5
LinkMore XV23 Lite 128GB	81.8 MB/s	77.3 MB/s, V60	97.4% of label	153.5 F	4.5/5
SUNEAST Ultimate Pro 128GB	53.5 MB/s	27.4 MB/s, V10	97.4% of label	140.0 F	3.5/5
Speederlash 128GB	47.0 MB/s	43.9 MB/s, V30	97.7% of label	132 F	4/5
Patriot EP 128GB	91.2 MB/s	20.8 MB/s, V10	94.5% of label	135 F	2.5/5

The VIOFO 32GB's sustained floor was published as 14.9 MB/s from July to September 2026, from the card's first-ever run. Two full re-runs on two readers measured 34.3 and 34.2 MB/s, and the row now carries the primary reader's figure like every other card. The review carries the correction and what the July run was.

The Gigastone High Endurance Pro's row carries its used-state floor, 31.0 MB/s, measured after the card had been written end to end, which is the state a dash cam keeps a card in. Fresh from the pouch the same card floors at 59.6, and a full SD erase from a native host brings that figure back. The review has both runs and the erase; the explainer has what a quick format, a full format and an SD erase each do, and which cards never showed the drop.

The SUNEAST Ultimate Pro's row carries its used state in both columns: 53.5 MB/s committed, and 27.4 through the worst ten seconds the rubric reads from its whole-card fill. New, the same card wrote 159.1 and held 31.0, and one fill took that away for good: a Raspberry Pi would not erase it, and a dash cam's own format left it as slow as before. The review has all four runs.

What the table shows

Six patterns across thirty-three cards

Thirty-three cards, one measurement chain. Read down the columns and the same shapes keep coming back, and not one of them is visible from a single review.

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were not the size on their label. The SanDisk ImageMate holds 34.3 GB behind a 128 GB label while passing Class 10, U3, A1 and V30, and three no-brand cards sold as 128 GB hold 48.0 to 66.4 GB. Every other card delivered between 94.5% and 100.1%, the low end the Patriot EP, which holds every byte it declares but declares the least of its label.

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cards that print a video speed class sustain a higher one, every one of them by at least a full class. Seven beat theirs by two, holding V90 against a printed V30: the PRO Ultimate, the PRO Plus, the P9 Express, the SanDisk Extreme, the Lexar Silver Plus, the Lexar Blue and the Amazon Basics. Ten of the rest hold exactly the class they print, and two fall below it: the SUNEAST Ultimate Pro holds V30 when new and V10 once it has been filled, and nothing an owner has restores it, and the Patriot EP holds V10 against a printed V30 new or used.

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cards that state a write speed miss it by a margin that matters: the VIOFO 128GB by 29%, the Newegg TeamGroup by 20%, the ProGrade by 17%. It runs the other way more often. Thirteen of the eighteen beat their claim, the SanDisk High Endurance most of all at 89.7 MB/s against a printed 40.

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never write at one steady speed. The Botslab cycles between 34 and 82 MB/s every 9.5 seconds, the TeamGroup between 5 and 83 every 2.7, the Speederlash between about 6 and 81 every 3.5, the PNY Premier-X between about 3 and 81 every 4.2, and the Gigastone on a nine-second saw-tooth. The FitcamX runs a 2.13 second rhythm that makes an honest card look broken, and the three no-brand fakes cycle faster than a one-second sample can draw. The five of them that print a V30 all hold it.

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change their speed class depending on the reader. The P9 Express carries PCIe on its second row of pins: V90 and 596.7 MB/s read on an Express reader, V60 and 89.7 on an ordinary one. The PRO Ultimate holds V90 on a reader that speaks Samsung's fast mode, V60 on the plain bus a camera gives it. Read speed moves with the reader far more often, which the reader test measures; which reader to buy is its own question.

1 name

covers two different cards. The VIOFO High Endurance 32GB and 128GB share a brand, a package and a product line, and their identity registers name two different manufacturers seventeen months apart.

CardCheck · the distribution

Where each card sits against the rest

A review can tell you a card held 88.0 MB/s. It cannot tell you whether that is good. Every ranking below is computed at build time from the same results files the table above prints, across 33 cards and 34 measured rows, and it is worth being blunt about what that makes it: these are percentiles of our bench, not of the market. We have tested these cards. We have not tested the ones we have never held, so n is printed beside every ranking on the page and you can weigh it yourself.

The rows are grouped by host bus and ranked only against their own group. Of the three buses represented here, UHS-I is the only one carrying enough cards (31) to support a ranking at all. Any bus below that line is listed with its measurements and no percentile, and earns one once it reaches eight cards.

UHS-I31 cards

Card	Label	Worst-10s sustained write	Committed sequential write	Peak temperature
Amazon Basics 128GB	128 GB	188.1 MB/sfastest of 31p98	189.4 MB/sfastest of 31p98	171 F27th coolest of 31p15
Lexar Silver Plus 128GB	128 GB	187.3 MB/s2nd fastest of 31p95	182.7 MB/s2nd fastest of 31p95	158.0 F22nd coolest of 31p31
Lexar Blue 128GB	128 GB	155.1 MB/s3rd fastest of 31p92	152.6 MB/s3rd fastest of 31p92	162.0 F24th coolest of 31p24
Samsung PRO Plus 512GB	512 GB	141.6 MB/s4th fastest of 31p89	142.2 MB/s4th fastest of 31p89	169.6 F25th coolest of 31p21
Samsung PRO Ultimate SD 512GB	512 GB	133.1 MB/s5th fastest of 31p85	137.3 MB/s5th fastest of 31p85	144.4 F16th coolest of 31p50
SanDisk Extreme 512GB	512 GB	127.6 MB/s6th fastest of 31p82	135.8 MB/s6th fastest of 31p82	172.3 F29th coolest of 31p8
SanDisk High Endurance 128GB	128 GB	88.0 MB/s7th fastest of 31p79	89.7 MB/s9th fastest of 31p73	151.4 F18th coolest of 31p44
Samsung P9 Express 256GB (UHS-I fallback)	256 GB	87.0 MB/s8th fastest of 31p76	87.7 MB/s10th fastest of 31p69	140.9 F14th coolest of 31p56
Samsung EVO Plus 128GB	128 GB	83.6 MB/s9th fastest of 31p73	82.0 MB/s13th fastest of 31p60	135.0 F10th coolest of 31p66
Vantrue Endurance PRO 128GB	128 GB	83.4 MB/s10th fastest of 31p69	84.7 MB/s12th fastest of 31p63	170 F26th coolest of 31p18
LinkMore XV23 Lite 128GB	128 GB	77.3 MB/s11th fastest of 31p66	81.8 MB/s14th fastest of 31p56	153.5 F20th coolest of 31p37
SanDisk High Endurance 512GB	512 GB	68.0 MB/s12th fastest of 31p63	135.0 MB/s7th fastest of 31p79	174 F30th coolest of 31p5
Kioxia Exceria G2 128GB	128 GB	62.6 MB/s13th fastest of 31p60	65.3 MB/s15th fastest of 31p53	143.3 F15th coolest of 31p53
SanDisk Ultra 128GB	128 GB	59.7 MB/s14th fastest of 31p56	60.7 MB/s17th fastest of 31p47	155.0 F21st coolest of 31p34
Metorage Industrial 64GB	64 GB	59.6 MB/s15th fastest of 31p53	60.5 MB/s18th fastest of 31p44	172.1 F28th coolest of 31p11
VIOFO High Endurance 64GB	64 GB	59.5 MB/s16th fastest of 31p50	61.2 MB/s16th fastest of 31p50	174.4 F31st coolest of 31p2
VIOFO High Endurance 128GB	128 GB	55.8 MB/s17th fastest of 31p47	57.0 MB/s21st fastest of 31p34	160.8 F23rd coolest of 31p27
Botslab 128GB (bundled)	128 GB	53.9 MB/s18th fastest of 31p44	59.0 MB/s19th fastest of 31p40	135 F10th coolest of 31p66
PNY Premier-X 128GB	128 GB	47.1 MB/s19th fastest of 31p40	53.6 MB/s22nd fastest of 31p31	129 F5th coolest of 31p85
Speederlash 128GB	128 GB	43.9 MB/s20th fastest of 31p37	47.0 MB/s25th fastest of 31p21	132 F7th coolest of 31p77
FitcamX 64GB (bundled)	64 GB	43.8 MB/s21st fastest of 31p34	47.1 MB/s24th fastest of 31p24	131 F6th coolest of 31p82
Silicon Power Superior Pro 128GB	128 GB	37.8 MB/s22nd fastest of 31p31	85.4 MB/s11th fastest of 31p66	123.7 F4th coolest of 31p89
Newegg TeamGroup 128GB	128 GB	35.5 MB/s23rd fastest of 31p27	39.8 MB/s26th fastest of 31p18	133 F9th coolest of 31p73
VIOFO High Endurance 32GB	32 GB	34.3 MB/s24th fastest of 31p24	35.3 MB/s27th fastest of 31p15	153.0 F19th coolest of 31p40
SanDisk ImageMate 128GB	128 GB	31.8 MB/s25th fastest of 31p21	33.2 MB/s28th fastest of 31p11	150.1 F17th coolest of 31p47
Gigastone High Endurance Pro 128GB	128 GB	31.0 MB/s26th fastest of 31p18	58.5 MB/s20th fastest of 31p37	132 F7th coolest of 31p77
SUNEAST Ultimate Pro 128GB	128 GB	27.4 MB/s27th fastest of 31p15	53.5 MB/s23rd fastest of 31p27	140.0 F13th coolest of 31p60
Patriot EP 128GB	128 GB	20.8 MB/s28th fastest of 31p11	91.2 MB/s8th fastest of 31p76	135 F10th coolest of 31p66
Generic LD 128GB	128 GB	14.6 MB/s29th fastest of 31p8	15.5 MB/s29th fastest of 31p8	111 F2nd coolest of 31p95
Generic MICRODRIVE 128GB	128 GB	12.8 MB/s30th fastest of 31p5	13.8 MB/s30th fastest of 31p5	118 F3rd coolest of 31p92
Generic PRO PLUS 128GB	128 GB	11.9 MB/s31st fastest of 31p2	12.5 MB/s31st fastest of 31p2	110 Fcoolest of 31p98

UHS-II2 cards

Two rows are not a distribution, so nothing on this bus is ranked. These are the measured figures, for reference. This bus earns percentiles at eight cards.

Card	Label	Worst-10s sustained write	Committed sequential write	Peak temperature
Lexar Professional 1667x 128GB	128 GB	109.5 MB/s	119.3 MB/s	142.7 F
ProGrade SDXC UHS-II V60 128GB	128 GB	102.8 MB/s	108.4 MB/s	145.1 F

SD Express1 card

One row is not a distribution, so nothing on this bus is ranked. This is the measured figure, for reference. This bus earns percentiles at eight cards.

Card	Label	Worst-10s sustained write	Committed sequential write	Peak temperature
Samsung P9 Express 256GB (SD Express)	256 GB	161.3 MB/s	212.9 MB/s	194.8 F

Six things these percentiles are not

Not the market. We have run 33 cards across this bench. A percentile here places a card among those and says nothing about the thousands we have never touched. Treat it as context for a number, never as a market share of quality.
Not one ladder. A UHS-II card and a UHS-I card are not competing for the same job, and ranking them together would hand the faster bus a placing it earned from its pinout rather than from its silicon. Each bus is scored only against itself, which is also why one card measured on two buses appears in two groups.
Not independent of capacity. Within UHS-I, label capacity and sustained write correlate at +0.41. Sustained write scales with the dies a card has to interleave, so a small card ranks low here partly for physics rather than for quality. The label sits in the table for exactly that reason.
Not a heat verdict. Peak temperature and sustained write correlate at +0.62 on this corpus: the quickest cards run the hottest, so the coolest card on the bench is frequently just the slowest one. That column is ranked so you can see the position, and its bar is left deliberately colorless so it cannot read as praise.
Not two opinions on write speed. The two write columns rank the same cards in almost the same order, at a rank correlation of 0.85. Read them as one finding measured two ways, not as two sources agreeing with each other.
Not a score. Scoring stays rubric-based and category-relative: a card is judged against the job it is sold for. A dash cam card that clears its camera's real duty many times over does not lose points for sitting low on a ladder built mostly of cards sold for harder work.

These are the same figures the corpus table prints, so any caveat attached to a number up there travels with its ranking down here, including the duty-dependent floor footnoted beneath the table.

The reviews

Read the full autopsies

Scored 2.5/5

Patriot EP 128GB

Patriot’s budget card prints no speed, only a 30 MB/s minimum sustained write, the V30 floor in words. It writes 91 MB/s for at least its first 4.4 GB, then 22.7, and held 22.5 MB/s through its worst ten seconds on two readers, so V30 and U3 fail. After one fill the fast stage is about 1 GB, and a discard and a format did not bring it back. Every byte verified, but at 94.55% of its label, and its registers match the Silicon Power Superior Pro’s.

Read the review

Scored 4/5

Speederlash 128GB

A no-name card whose pack prints U1 where the card itself prints U3. It held U3 and V30 through its worst ten seconds on two readers, 43.94 MB/s after a write of the whole card, verified every byte of 125.1 GB, and writes in a three-and-a-half-second rhythm under a steady 47 MB/s. It reports the Gigastone High Endurance Pro’s identity and capacity to the byte, and writes nothing like it.

Read the review

Scored 3.5/5

SUNEAST Ultimate Pro 128GB

SUNEAST’s card prints a 208 MB/s read in DDR225 mode and no write speed. Fresh, it wrote 159 MB/s for about 15.7 GB and held V30; after one write of the whole card it fell to V10 on both readers, and neither a Raspberry Pi erase nor a dash cam format brought it back. It read 181 MB/s on SanDisk’s own reader, and every byte verified.

Read the review

Scored 4.5/5

LinkMore XV23 Lite 128GB

LinkMore’s budget card prints 100 MB/s read and 85 write, and delivers both by the bench’s rules. It held 77.3 MB/s through its worst ten seconds, V60 against a printed V30, wrote the whole 124.6 GB at about 80 MB/s with no cache to run out of, and was no slower after a fill. Its identity registers match the SUNEAST Ultimate Pro’s, a card that measured nothing like it.

Read the review

Scored 4/5

Metorage Industrial 64GB

It came inside a Mercylion G401 dash cam and prints no speed at all. Its registers match the VIOFO High Endurance 64GB's apart from the serial and the build date, and on the same reader it lands within 1.2% of that card on every write figure: 60.5 MB/s committed, 59.6 through its worst ten seconds, V30 held on two readers, every byte verified, and 172.1 F under load.

Read the review

Scored 4/5

Silicon Power Superior Pro 128GB

Silicon Power’s everyday card prints no speed at all, and its website promises 80 MB/s write. Measured, it writes 85.4 MB/s for the first 4.7 GB, then a flat 39 for as long as you keep going, which holds V30 with a quarter to spare. Every byte verified, 123.7 F under load, and an identity register carrying Silicon Power’s initials under an ID the Linux kernel names Kingston’s.

Read the review

Scored 4.5/5

PNY Premier-X 128GB

The entry-tier card that prints a read speed and declines to print a write speed. Measured, the write is 53.6 MB/s committed in a four-second cache cycle; V30 holds at 47.4 MB/s on both readers, every byte verified twice, 129 F under load, and the capability registers put it on the TeamGroup and Gigastone platform under a PNY identity.

Read the review

Scored 4.5/5

Amazon Basics 128GB

The question people keep asking, answered on two readers. Longsys silicon under Amazon's name: 156 MB/s sustained on the ProGrade, 188 on a SanDisk QuickFlow, the 200 read claim beaten without Amazon's own reader, every byte verified, and 171 F against an 80 C rating.

Read the review

Scored 4.5/5

Gigastone High Endurance Pro 128GB

The first card on the bench to print TLC on its face, in a pouch that prints nothing else. It holds V30 in both of its states: 59.6 MB/s through its worst ten seconds fresh from the pouch, 31.0 once the card had been written end to end, and back to 54.5 after a native-host SD erase. Every byte verified, and among the coolest cards here.

Read the review

Scored 4/5

VIOFO High Endurance 64GB

The middle capacity of a line tested three times over, supplied by VIOFO with an A119M Pro. It prints 40 MB/s and holds 59.5 through its worst ten seconds on two readers, verifies every byte, and runs at 174 F doing it, the hottest of the three VIOFO capacities.

Read the review

SanDisk High Endurance 512GB microSD review, a used dash cam card that holds V60 and stalls for 3.6 seconds on two readers

Scored 4/5

SanDisk High Endurance 512GB (used)

A used card with real dash cam service history. It reads 180 MB/s, holds V60 against a printed V30 and verified all 511.8 GB twice, then stopped writing for 3.6 seconds mid-stream, on two readers, thirteen times in three hours. No other card here has ever done that.

Read the deep dive

Scored 4.5/5

Vantrue Endurance PRO 128GB

A dash cam card that prints no read speed, no write speed and no endurance rating, then beats the one class it does print by 2.8x and verifies every byte. Its one measured weakness is heat: the highest peak of any 128GB card on this bench, in an air-conditioned room.

Read the deep dive

Three generic 128GB microSD cards labelled PRO PLUS, MICRODRIVE and LD, all three tested and found to hold about half of what they claim

Scored 1/5 each

Three $11 no-brand 128GB cards

Three no-brand cards bought in one order, identical packaging, three names. All three report 134.2 GB and hold 48 to 66 of it, and not one raised a read error while losing the rest. Only writing the whole card finds it.

Read the test

Scored 4.5/5

Lexar Blue 128GB

Lexar's cheapest tier prints one speed number and no write figure, then beats the claim it does print and holds 155.1 MB/s, level with the pricier Silver Plus on the same reader. On a faster reader the Silver Plus pulls ahead; the Blue does not.

Read the deep dive

SanDisk Ultra 128GB microSD review, a used card dated to September 2018 with all 127.8 GB verified byte for byte

Scored 4.5/5

SanDisk Ultra 128GB (used, 2018)

The card most people already own, and the one that promises least: a 10 MB/s floor, no published write speed anywhere in the line, and no video class. It beat that floor six times over and verified every byte after nearly eight years.

Read the deep dive

Samsung EVO Plus 128GB microSD review, a seven-year-old used card with all 128 GB verified byte for byte

Scored 5/5

Samsung EVO Plus 128GB (used, 2019)

The only used card on the bench and the only one that prints no speed at all. Its own CID register dated it to June 2019, and then all 128 GB wrote and read back with zero bad bytes…

Read the deep dive

Lexar Professional Silver Plus 128GB microSD review, 187 MB/s sustained on the right reader, bundled free with a dash cam

Scored 4.5/5

Lexar Silver Plus 128GB (bundled)

It came free in a dash cam box and then outwrote almost every card here, including 512 GB cards that cost real money. 157.0 MB/s committed on the ProGrade, 182.7 on a SanDisk QuickFlow, no cache cliff anywhere, and a camera that cannot use a byte of it…

Read the deep dive

Scored 4.5/5

SanDisk Extreme 512GB

Beats its printed 190 MB/s read at 193.3 on a host that can show it, holds V90 against a printed V30, and returns every byte of 512 GB. It is also the slowest small-file writer of its class.

Read the deep dive

Scored 4.5/5

Samsung PRO Plus 512GB

The fastest sustained writer on this bench that is not on a PCIe bus, and it beat several UHS-II cards costing more. It exceeds its own printed 130 MB/s write at 142.15, holds its speed flat across all 512 GB with no cache cliff anywhere…

Read the deep dive

Scored 4/5

Samsung P9 Express 256GB

The first microSD Express card on the bench, and the first tested twice on one day because it has two personalities. Its second row of pins carries PCIe, not a faster SD bus…

Read the deep dive

Scored 3.5/5

Newegg TeamGroup 128GB

The cheap card that turned out to be completely real, and completely slow. Every byte of its capacity is there and verified, and it holds every class mark it prints…

Read the deep dive

Samsung PRO Ultimate 512GB full-size SD review, a UHS-I card whose video speed class changes with the reader you put it in

Scored 4.5/5

Samsung PRO Ultimate SD 512GB

The first 512GB card on the bench, and the first whose printed speed the standard interface cannot reach at all. It beat the 130 MB/s write on its own face, handed over 100.13% of half a terabyte with zero mismatched bytes…

Read the deep dive

ProGrade SDXC UHS-II V60 and Lexar Professional 1667x review, two full-size UHS-II cards badged V60 that both sustain V90

Scored 4/5 and 4.5/5

ProGrade V60 + Lexar 1667x 128GB

The first full-size SD cards on the bench, and the first UHS-II. Two cards that agree on every number a shopper can read: 128GB, UHS-II, V60, 250 MB/s…

Read the deep dive

Scored 4/5

FitcamX 64GB (bundled)

The card in the FitcamX box wears a look-alike SD logo where the licensed one belongs, and then holds every byte of its 64GB anyway. Its speed graph appears to fall apart twice a second…

Read the deep dive

Scored 4.5/5

Botslab 128GB (bundled)

The card taped inside a dash cam box, and the strangest write curve on this bench. It cycles between 34 and 82 MB/s every nine and a half seconds, for as long as you care to watch, and still never drops below the V30 floor it prints…

Read the deep dive

VIOFO High Endurance 32GB and 128GB review, two cards sold under one name that came from two different manufacturers

Scored 3.5/5 and 4/5

VIOFO High Endurance 128GB + 32GB

The first pair we tested as a matched set, and they turned out to be two unrelated cards wearing one name. Their identity registers name two different manufacturers, seventeen months apart…

Read the deep dive

Scored 1/5

SanDisk ImageMate 128GB

A counterfeit, and the most interesting one we have seen: it holds 34.3 GB against a 128 GB label while passing Class 10, U3, A1 and V30. Fast flash, fraudulent number. It is the proof that you cannot catch a fake card by benchmarking it.

Read the autopsy

Scored 4.5/5

Kioxia Exceria G2 128GB

The card that came with your dash cam, and the standard advice to bin it is wrong. It beat its published write spec by 31% and did not fade at all under loop-recording churn…

Read the deep dive

Scored 5/5

SanDisk High Endurance 128GB

The card that under-sells itself. It committed writes at 89.7 MB/s against a printed 40, held V60 against a printed V30, delivered all 128.0 GB with zero mismatched bytes…

Read the deep dive

Beyond cards

The bench tests its own gear too

CKBench is not only for review samples. Before a piece of storage earns a job on this bench, it gets the same suite as everything else, and the first one through was a USB flash drive about to become the boot device for our card-identity rig. It is not a memory card, so it is scored on its own terms and stays out of the card table above. It also produced the strangest finding on this page: a drive whose read speed depends on how the data on it was written.

Scored 4/5 as a flash drive

SanDisk Ultra Fit 32GB

The thumb drive that beat its only printed number and hid everything else. 148.8 MB/s read against a claimed 130, full capacity verified with zero bad bytes…

Read the bench notes

Start here

What buyers actually ask

Should I replace the card that came with my dash cam? Probably not, and we have now tested five of them. The bundled Kioxia beat its own spec and handled loop recording without flinching, and the Lexar Silver Plus that replaced it in the next camera outwrites every card on this bench, retail ones included.

How do I tell if my card is fake? Not with a benchmark. Check the reported size first, then fill the whole card with verifiable data and read it all back. The counterfeit we tested passes every speed test there is.

Why does my 128GB card only show 119 GB? That is normal. Your computer counts in binary, so 128,000,000,000 bytes displays as about 119 GB. Nothing was taken. A real shortfall looks very different, and the Kioxia review explains where the missing gigabytes on that card actually went.

Do I need a special card for a Nintendo Switch 2? Yes, it needs microSD Express, and the marking to look for is EX. An ordinary microSD will not run games on it, and a UHS-II card will not either: both rows of pins look alike but carry different signals. We tested one on two readers to show what the format actually delivers.

Which of these should I actually buy? Answer three questions in the card finder and it names one or two. If you would rather see the working, the full card picker takes a specific camera and lays every measurement out side by side against it.

How much footage fits on a card? Work it out for your own camera's bitrate in the dash cam storage calculator.

What does the endurance rating on a card mean? Less than it looks. Every hours ladder SanDisk and Samsung publish is exactly linear in capacity, so the figure is the capacity times a constant, and the bitrate that gives it meaning is printed on the box rather than in the datasheet. The endurance-rating explainer shows the arithmetic and what the bench measures instead.

Do you only test memory cards? No. Anything storage can go on the bench, and the gear we rely on ourselves goes on first. The SanDisk Ultra Fit 32GB got the full suite before we trusted it to boot our card-identity rig.

The method

How these numbers are produced

Every figure on this page comes from one results file per card, written by a bench built for this: writes are committed and confirmed before the timer stops, a cache-leak canary aborts the run if the operating system serves a cached read, and every test byte is seeded so it can be verified on the way back. Cards are scored on five dimensions against the job they are sold for, and a card that misrepresents its capacity is capped at 1 out of 5 no matter how fast it is.

The full method, the rubric, the unit conventions and an honest list of what we deliberately do not test are all on one page. Alongside it sits the reference we built while identifying these cards: every SD manufacturer ID we have decoded, and an honest account of what that number can and cannot prove.

How we test and score memory cards

The bench, the five-dimension rubric, the conventions, and the gaps we will not paper over.

Read the method

SD card manufacturer IDs, decoded

Look up the CID register your own card reports, and see why a matching manufacturer ID does not make a card genuine.

Read the register