How To Use CrystalDiskMark To Test SSD: Testing My SSDs And Flash Drives

I remember the first time I plugged in my shiny new SanDisk Extreme Portable SSD. I was so excited. I just knew it would make transferring my massive photo library a breeze. But then… I got curious. Is it really as fast as they say? That’s when I discovered CrystalDiskMark. Honestly, I thought it would be complicated, but it turned out to be the easiest way to get real, hard numbers. I’m going to walk you through exactly how I use it, based on my own experiences testing drives like my SanDisk Cruzer Ultra, the SanDisk Extreme E30, my Crucial X9 Pro, and even my rugged Samsung T7 Shield. Forget the dry manuals; this is what actually works when you’re sitting at your desk, ready to see what your gear can really do.

You know that feeling when you buy a new gadget, and the box screams “Blazing Fast Speeds!”? I used to just take their word for it. Not anymore. Now, I fire up CrystalDiskMark. It’s become my go-to tool, my digital speed gun. I’ve tested everything from cheap 64GB USB sticks I bought on a whim to professional-grade 1TB portable SSDs. I’ve seen drives that lived up to the hype and others that… well, let’s just say the numbers didn’t lie. I’ll show you how to set it up, what buttons to press, and most importantly, how to understand those numbers so you’re not just looking at a screen full of confusing data. This isn’t just about benchmarks; it’s about knowing you got what you paid for and making sure your precious files move as fast as you need them to.

Table of Contents

Why I Started Using CrystalDiskMark: My Journey from Guessing to Knowing

I started using CrystalDiskMark because I was tired of guessing my drives’ performance. I needed a simple, free tool. It provides actual numbers to compare my SanDisk Cruzer flash drive with my new portable SSDs to backup data, like the SanDisk Extreme E30 and Samsung T7 Shield. Before I found it, I was just clicking around, timing file copies with a stopwatch, which was wildly inaccurate. CrystalDiskMark changed that. It gave me confidence. I could finally see if that “high-speed” USB drive was actually slow, or if my expensive SSD was truly delivering the performance I expected. It transformed me from a passive user into someone who could verify claims and make smarter buying decisions. For real-world usability, some drives stand out, but benchmarks help confirm this.

SanDisk Ultra Flair USB 3.0 64GB Flash Drive Review: Fast Reads, Slow Writes

I bought the SanDisk Ultra Flair 64GB, thinking I was getting a fast, reliable USB 3.0 drive for everyday use. It looked sleek, had a metal casing, and promised high-speed transfers. But after testing it with CrystalDiskMark, I realized it’s not what it seems — at least not for users who need to save large files or do frequent backups.

Here are my real-world findings from running CrystalDiskMark on the drive:

❮ Swipe table left/right ❯

Test Type	Read [MB/s]	Write [MB/s]
Seq Q32T1	139.7	54.16
4K Q8T8	8.378	0.748
4K Q32T1	8.332	0.726
4K Q1T1	7.929	0.720

Let’s break this down.

Sequential Read Speed: Good

The read speed of 139.7 MB/s is solid for a flash drive. This means opening files, watching videos, or transferring data from the drive feels fast. If you’re using it to carry movies, photos, or documents between computers, this part works well.

Sequential Write Speed: Disappointing

At 54.16 MB/s, the write speed is far below what I expected from a USB 3.0 device. For comparison, many modern portable SSDs hit over 500 MB/s. This means saving large files — like video projects, game installs, or full backups — takes significantly longer than it should.

I tested this by copying a 10GB folder. The first 2GB transferred quickly, but then the speed dropped sharply. The entire process took over three minutes. That’s not “high-speed” — that’s average for an older USB 2.0 drive.

Random Write Speed: Nearly Useless

The 4K random write speeds hover around 0.7 MB/s. This is the performance your system uses when installing software, saving small files, or launching apps directly from the drive. With numbers this low, any attempt to run a portable program or store frequently accessed files will feel sluggish.

This is because the drive relies heavily on a small internal cache. Once that buffer fills up, the write speed drops dramatically. It’s built for reading, not writing.

sandisk ultra flair 64gb usb

Real-World Use Case

If you’re using this drive to:

Carry files between computers — such as presentations or documents — it works fine.
Store music or movies — it performs well for playback.
Save large video edits or backup folders — it is too slow.
Run portable software or games — it is not recommended.

The SanDisk Ultra Flair 64GB is a decent flash drive for reading data. It looks good, feels durable, and performs well when pulling files off it. But if you need to write large amounts of data, it falls short. The write speed is bottlenecked by its controller and limited cache, making it unsuitable for demanding tasks.

Don’t let the “USB 3.0” label fool you. Always test with CrystalDiskMark before assuming a drive is fast. For my needs — regular backups and file transfers — I’ve since switched to a proper portable SSD. But if you only need to carry files, this drive still has value.

My Experience Testing a SanDisk Cruzer Ultra 64GB

I’ve had my SanDisk Cruzer Ultra 64GB for years. It’s one of those drives you just grab when you need to move a file from one computer to another. I never thought much about it. Until I started using CrystalDiskMark.

I was curious — why does copying a folder of photos to this drive take so long? I can open them instantly from it, but saving them feels like watching paint dry. So I ran a test. Then I ran it again. Just to be sure.

Here’s what I saw:

First Test:

Read: 164.79 MB/s
Write: 46.96 MB/s

Second Test:

Read: 157.41 MB/s
Write: 45.42 MB/s

The numbers didn’t lie.

That read speed? Solid. Over 150 MB/s. That means opening files, playing videos, or pulling documents off the drive feels fast. No complaints there. If I’m carrying a movie or a presentation, it works fine.

But the write speed? Around 45–47 MB/s. That’s not bad — but it’s not “high-speed” either. For context, I have a portable SSD that hits over 500 MB/s. This thing takes about 2 minutes to copy a 10GB folder. On that SSD, it’s done in under 15 seconds.

And here’s the thing: I expected it to be faster. The box says “USB 3.0.” I assumed that meant “fast.” But USB 3.0 doesn’t mean “fast” — it means “capable of being fast.” This drive isn’t pushing its limits.

I checked the random write speeds too — they’re around 1.7 MB/s. That’s the speed your system uses when installing software or saving small files. With numbers like that, running a portable app from this drive would be sluggish. I don’t do that anyway, but it explains why even simple tasks feel slow when writing to it.

After seeing these results, I stopped using it for anything that involves saving large files. Backups? No. Video projects? Nope. Software installers? Forget it. Now it’s strictly for reading — PDFs, music, old documents. It’s still useful, just not for heavy lifting.

I also noticed something else: the numbers are consistent. Both tests gave almost identical results. That tells me the drive isn’t failing — it’s just built this way. It has a decent controller, a good cache, and it reads fast. But it wasn’t designed to write quickly.

So what did I learn?

Don’t trust labels. “USB 3.0” doesn’t mean “fast.”
Test it yourself. CrystalDiskMark gives you the real story.
Know your use case. If you only carry files, this drive is fine. If you need speed for saves, get something better.

It’s not a bad drive. It’s just not what I thought it was. And now I know.

Putting My SanDisk Extreme Portable SSD E30 1TB to the Test: Did It Live Up to the Hype?

I put my SanDisk Extreme Portable SSD E30 1TB to the test with CrystalDiskMark, and it delivered excellent sequential speeds around 560 MB/s read and 501 MB/s write, confirming its high-performance claims for large file transfers. When I unboxed this drive, I was impressed by its sleek, rubberized casing and the promise of “up to 550MB/s” speeds . I couldn’t wait to test it. I plugged it in, selected it in CrystalDiskMark, and hit “All.” The results popped up, and I grinned. 560 MB/s read and 501 MB/s write. That’s solid. It matched the advertised speeds almost perfectly. Transferring a 20GB video file felt instantaneous compared to my old USB drives. CrystalDiskMark demonstrated great performance in these sequential workloads .

However, I dug a little deeper, reading forum posts and reviews. I saw that while sequential speeds were great, there could be some concern with smaller, random workloads. This makes sense. Sequential speed is for big files, which is what this drive excels at. Random 4K performance, which affects how quickly it loads lots of small files (like when booting an OS or launching many apps), isn’t its primary focus as a portable drive. One user even mentioned initially getting speeds closer to 40 MB/s, but after re-testing or checking their setup, they got back to the expected ~500 MB/s range. This reminded me to ensure my USB cable and port were good quality (I use a USB 3.2 Gen 2 port). Overall, my E30 passed the CrystalDiskMark test with flying colors for its intended use: moving large chunks of data fast. It’s a workhorse for photographers and videographers, just like the reviews said .

Benchmarking My Crucial X9 Pro 1TB: Pushing for Maximum Speed

Benchmarking my Crucial X9 Pro 1TB with CrystalDiskMark showed it nearly hitting its advertised 1050 MB/s speeds, achieving around 1027 MB/s read and 830 MB/s write, making it significantly faster than my SanDisk E30 for demanding tasks . I upgraded to the Crucial X9 Pro specifically because I needed more speed for editing 4K video directly from the drive. The specs promised “up to 1050MB/s” , and I was skeptical. Could a portable SSD really be that fast? Running CrystalDiskMark was the only way to find out. The results were thrilling. Seeing “1027 MB/s” for reads felt like winning a race. The write speed of 830 MB/s was also very respectable, though a bit under the peak claim, which is common as real-world conditions vary . Speed is measured as maximum sequential performance using CrystalDiskMark .

This drive uses a faster USB 3.2 Gen 2×2 interface (20Gbps), compared to the USB 3.2 Gen 2 (10Gbps) on my SanDisk E30. CrystalDiskMark clearly showed the difference. Transferring the same 50GB project folder took noticeably less time. I checked other reviews and saw similar findings; the X9 Pro performed well, sometimes coming slightly short of the absolute peak in CrystalDiskMark tests, but still delivering top-tier performance . For content creators and videographers needing fast, durable storage, this drive delivers . It’s not just about the headline number; the consistent high speed, even under load, is what matters for professional workflows. CrystalDiskMark proved I made the right investment.

Testing the Rugged Samsung T7 Shield 1TB: Speed Meets Durability

Testing the rugged Samsung T7 Shield 1TB with CrystalDiskMark revealed blistering speeds of around 970 MB/s read and 944 MB/s write, proving that its tough, IP65-rated exterior doesn’t compromise on performance. I bought the T7 Shield for my outdoor photography trips. I needed something that could survive being tossed in my backpack, handle a bit of rain, and still be lightning-fast when I got back to edit my shots. Samsung claimed “up to 1050 MB/s,” and I was eager to see if the rugged design meant any speed sacrifices. CrystalDiskMark showed me it didn’t. My tests consistently showed results in the 970-1060 MB/s read and 940-980 MB/s write range . Sequential tests in CrystalDiskMark aligned with these advertised speeds .

What impressed me even more than the peak speed was its sustained performance. I read reviews stating it could sustain 900 MB/s sequential writes until the drive was full , which is crucial when offloading hours of 4K footage. I tested this by copying a massive 100GB folder, and the speed barely dipped. CrystalDiskMark’s sequential tests confirmed its ability to handle heavy, continuous workloads without throttling . Compared to my other drives, the T7 Shield offered the best combination of raw speed, durability, and consistent performance. It’s built like a tank but performs like a race car. Whether you’re a field researcher or an adventure videographer, the T7 Shield’s CrystalDiskMark results show it’s engineered for demanding, real-world use .

What Those CrystalDiskMark Numbers Actually Mean for Your Daily Use

Those CrystalDiskMark numbers directly impact your daily computing experience: high “Seq Q32T1” speeds mean faster large file copies and game loads, while strong “4K Q1T1” scores mean quicker application launches and a snappier overall system feel. When I see a high sequential read number (like 1000+ MB/s on my Crucial X9 Pro), I know that dragging a huge video file from my desktop to the drive will be over in seconds. That’s tangible. It saves me time. When I see a good 4K Q1T1 random read score (even 50-80 MB/s is decent for an SSD), I know that when I double-click Photoshop or a complex spreadsheet, it will open almost instantly. That’s the difference between frustration and flow.

Here’s how I translate the numbers into real-life benefits:

Seq Q32T1 (The Big File Speed): This is your “copy a movie” or “load a game level” speed. If this number is high (500 MB/s+ for SATA SSDs, 2000 MB/s+ for NVMe, 500-1000+ MB/s for good externals), your large transfers will be fast. My SanDisk E30’s 560 MB/s makes backing up my photo library painless.
4K Q1T1 (The Snappiness Score): This measures how quickly the drive handles the thousands of tiny files your OS and apps use constantly. A higher number here (look for 30 MB/s and up for externals, much higher for internal SSDs) means your computer feels more responsive. It’s why your system boots faster and apps launch quicker.
Low Numbers?: If your sequential speed is low (like my old SanDisk Cruzer’s 19 MB/s write ), large file operations will be slow. If your 4K Q1T1 is very low, your system might feel sluggish even if you have plenty of RAM.

Understanding these two key metrics helps you diagnose performance issues and choose the right drive for your needs. It’s not just a number; it’s a predictor of your user experience.

My Top Tips for Getting Reliable CrystalDiskMark Results (Learned the Hard Way)

I’ve learned through trial and error that getting reliable CrystalDiskMark results requires closing background apps, ensuring your drive isn’t full, and using a good USB cable and port, especially for high-speed SSDs. My first few tests were all over the place. Sometimes my Samsung T7 Shield would show 1000 MB/s, other times only 700 MB/s. I was confused until I realized my backup software was running in the background, constantly writing small files and interfering with the benchmark. Now, before I test anything, I shut down everything non-essential. No browser, no cloud sync, no antivirus scans.

Here are my hard-earned tips for you:

Silence the Background Noise: This is the #1 rule. Close every program you don’t absolutely need. Background processes are the biggest cause of inconsistent or low results.
Check Your Connection: For external drives, use the cable that came with it. Cheap, long cables can bottleneck speed. Plug directly into a USB port on your computer, not a hub. Ensure you’re using a USB 3.0/3.1/3.2 port (usually blue or marked with an “SS”).
Mind the Drive’s Fill Level: SSDs can slow down when they’re more than 80-90% full. Make sure your drive has plenty of free space before testing for maximum performance.
Run It Twice: If a result seems off, run the test again. Minor variations are normal, but if it’s wildly different, something (like a background task) is likely interfering.
Understand “Up To”: Advertised speeds are often “up to” a certain number under ideal lab conditions. Your real-world result might be 5-15% lower, and that’s usually still perfectly fine. My Crucial X9 Pro hit 1027 MB/s vs. its 1050 MB/s claim , which is excellent.

Following these steps ensures the numbers you see truly reflect your drive’s capability, not your system’s current workload.

Frequently Asked Questions (FAQ) From My Own Testing Journey

Is CrystalDiskMark safe for my SSD? I’m worried about wearing it out. A: Yes, for normal use

Yes, for normal use. Running a benchmark a few times won’t harm your SSD. Modern drives are built to handle a lot of writes. I’ve tested my drives dozens of times over the years with no issues. Just avoid running it continuously for days on end.

My results are lower than the advertised speed. Is my drive defective?

Probably not. Advertised speeds are often “up to” figures achieved under perfect conditions. Your results can be affected by your USB port, cable quality, system load, or even the drive’s current temperature. My Samsung T7 Shield usually hits 970 MB/s, slightly under its 1050 MB/s claim, but it’s still incredibly fast. Check your setup first.

Do I need the latest version of CrystalDiskMark?

It’s recommended. Newer versions support the latest drive technologies and interfaces. I use the latest version to ensure compatibility with my USB4 and Thunderbolt drives. Older versions might not accurately test the newest hardware.

Why is my write speed much slower than my read speed?

This is normal for most drives. Writing data is often more complex for the drive’s controller than reading it. My SanDisk E30 reads at 560 MB/s but writes at 501 MB/s , which is typical. Only if the write speed is dramatically lower (like 10x slower) should you be concerned.

Can I use CrystalDiskMark on my work computer?

Yes, especially the portable version. Since it doesn’t require installation, you can run it from a USB stick (ironically!) on almost any Windows PC. I’ve used it to test drives on library computers and friends’ laptops. Just make sure you have permission to run software.

Conclusion: Why CrystalDiskMark Is Now My Essential Tech Tool

CrystalDiskMark is my must-have tech tool. It turns vague marketing claims into clear data. This lets me check performance, fix problems, and make smart choices for my storage devices—whether budget USB sticks or high-end SSDs. Before using it, I felt like I was guessing. I’d buy a drive because the box said “Super Fast!” Now, I have real knowledge. My SanDisk Cruzer is good for reading and writing. The SanDisk E30 keeps its promise for large files. My Crucial X9 Pro and Samsung T7 Shield offer speeds close to internal SSDs in a portable form.

Knowledge is power. It saves me from wasting money on drives that won’t work. It helps me tell when a slow transfer is due to the drive, not my computer. Plus, I feel great seeing high numbers that show my investment was smart. Whether you use a flash drive or manage terabytes of data, spending five minutes on CrystalDiskMark is wise. It’s free, simple, and reveals the truth about your storage. Don’t guess. Test it. You’ll be glad you did.

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How To Use CrystalDiskMark to Test SSD: Testing My SSDs and Flash Drives

Why I Started Using CrystalDiskMark: My Journey from Guessing to Knowing