Why so slow?

Ran Winsat pointing it to my "C" drive, a 512GB NVMe PCI3 SSD. The results were not stellar:

> Disk Random 16.0 Read 472.47 MB/s 8.2
> Disk Sequential 64.0 Read 2561.93 MB/s 9.1
> Disk Sequential 64.0 Write 795.96 MB/s 8.3
> Average Read Time with Sequential Writes 0.234 ms 8.5
> Latency: 95th Percentile 1.521 ms 7.9
> Latency: Maximum 4.416 ms 8.6
> Average Read Time with Random Writes 0.201 ms 8.9
> Total Run Time 00:00:05.28

Why would the write speed be so slow? I also ran Crystal Disk and I -assume- it used the "C" drive as I could not find any setting that would change it.


It's the original SSD that came with my Lenovo T7 Desktop. I've always felt writing was slow but I was blaming it on Windows. Perhaps Lenovo just stuck in a lousy SSD? I could certainly swap it out for a new one.

The "C" drive is a Samsung MZVLB512HBJQ-000L7 which Samsung claims has a 2900MB/s sequential write speed. So something seems amiss.

It is pointing at your C drive. Use the drop-down arrow to test other drives.

Have you run trim on the drive? An Easy Way to Enable or Disable TRIM on SSD Windows 11/10

In Windows Explorer, right click on the drive. Choose Properties. Tools tab. Optimize button.

I'm not sure what to expect for an SSD that is 84% full.

Scott said:

It is pointing at your C drive. Use the drop-down arrow to test other drives.

(snip)

Click to expand...

That seems to be answering a question that wasn't asked.

Checked for updates; showed nothing but a Defender update. Then looked in the "optional" area and found four items. Did those updates and restarted. Ran winsat again and it showed a write speed of about 2800MB/s so maybe a missing firmware update or driver?

That second Intel driver (30.100.1841.2) is for Windows 10 according to the MS Update Catalog. The first one (17.8.1.1066) does look like it's a SCSI driver so maybe that's the guy my system was missing. My Lenovo had been running Win10 since I bought it four(?) years ago and I did a nuke and pave into Win11 a couple of months ago.

Also: @bobkn - Following your advice, I did check for TRIM status:
NTFS DisableDeleteNotify = 0 (Allows TRIM operations to be sent to the storage device)
ReFS DisableDeleteNotify = 0 (Allows TRIM operations to be sent to the storage device)
...so that looks okay. Thank you!

Winsat. Jeepers, I forgot that was still present.

Ran CrystalDiskMark again (post-updates). Still shows sucky performance:

...and winsat now shows a sequential write speed of 1063MB/s (was 2900 just after a restart). I'll restart and check it again.

bobkn said:

That seems to be answering a question that wasn't asked.

Click to expand...

rumplestiltskin said:

assume- it used the "C" drive as I could not find any setting that would change it.

Click to expand...

Not really a question, more of a statement.

rumplestiltskin said:

Ran CrystalDiskMark again (post-updates). Still shows sucky performance:
View attachment 142843
...and winsat now shows a sequential write speed of 1063MB/s (was 2900 just after a restart). I'll restart and check it again.

Click to expand...

Seems about right to me.
Even on CrystalMark site, the same pattern is shown.
Probably because it is using 4kb with only 1 queue in the last one.

Nothing much is amiss, your testing shows that it is broadly in line with the manufacturers specs.
They always pick the highest numbers possible.

The low write speed is probably due to it being at 84% capacity plus Housekeeping functions and maybe Thermal limits, Power saving measures, OEM Laptop firmware.

Helmut said:

Nothing much is amiss, your testing shows that it is broadly in line with the manufacturers specs.
They always pick the highest numbers possible.

The low write speed is probably due to it being at 84% capacity plus Housekeeping functions and maybe Thermal limits, Power saving measures, OEM Laptop firmware.

Click to expand...

Did a cleanup through Settings > Storage which dropped the used space to 38%. All power settings are at 100%. Energy Saver is off except for screen sleep in 10 minutes. This is a T7 Desktop; I know there's a T7 laptop but that's not my machine. The CPU is water-cooled and never runs hot. I have everything set to ramp up fans when required instead of dropping power. BTW: I haven't done any tweaks to the CPU.

I'm going to try one more restart and run winstat a few times over the course of a couple of hours. I'll note that, upon a restart, running CrystalDiskMark immediately shows lousy write #'s. Winstat upon a restart looks fine (about 2900 MB/s write) but, as soon as I run CrystalDiskMark (and get the lousy numbers), then return to run winstat again, now I get lousy numbers. In short: CrystalDiskMark always shows lousy write numbers. Ugh.