Poor NVMe performance on Dell Optiplex 7080

lumencreative · 28 Mar 2021 at 20:37

Recently bought a few Dell Optiplex 7080's from the Dell refub store to replace some aging 3020/7020's we have. We opted for the 7080 because we wanted to have two NVMe drives installed one for OS/Apps and one for a cache drive for Photoshop as we use a lot of large Photoshop files.

The Optiplexs came with Dells 'Class 35' drives which in our case were WD SN520's. I have bought some Adata SX8200 Pro drives to go in the second NVMe slot, which should have a read speed of 3500MB/s and a write speed of 3000MB/s.

As you can see from the poor photos of the CrystalDiskMark results, I am getting near the expected speed for the SN520, but nowhere near 3500/3000MB/s for the Adata, and I was wondering if there's anything I need to check in the bios.

Is slot one (the one the SN520 is installed in) generally a better performing slot?

Any recommendations greatly appreciated.

SN520 Speeds

Adata Speeds

tamzzy · 28 Mar 2021 at 20:49

those look like PCIe 3 x2 speeds
could you confirm the mobo configuration?

also: https://www.overclockers.co.uk/forums/threads/buyers-beware-sx-8200-pro.18910311/

lumencreative · 28 Mar 2021 at 20:54

tamzzy said:
those look like PCIe 3 x2 speeds
could you confirm the mobo configuration?

also: https://www.overclockers.co.uk/forums/threads/buyers-beware-sx-8200-pro.18910311/

According to the specifications, the slots should both be PCIe 3 Gen x4

tamzzy · 28 Mar 2021 at 20:57

lumencreative said:
According to the specifications, the slots should both be PCIe 3 Gen x4

try the adata in slot one, and leave slot 2 blank

lumencreative · 28 Mar 2021 at 21:00

tamzzy said:
try the adata in slot one, and leave slot 2 blank

Thanks, going to try that when I get to work tomorrow. Ideally wanted to leave the SN520 in (its a mini NVMe which won't fit in the 2nd slot as the 2nd slot doesn't have the screw hole to secure it).

Kautya · 29 Mar 2021 at 08:48

On my asus motherboard, I had to set the bandwidth configuration to x4 from the bios settings. Might be worth checking if that is something you'll have to do that as well.
Shown on the last image on this url - https://uk.crucial.com/support/articles-faq-ssd/bios-uefi-configuration-optimizing-m2

lumencreative · 29 Mar 2021 at 10:47

I have tried the Adata drive in the other slot this morning and still get the same performance as before. I noticed in the bios that rather than AHCI mode, Dell set it to RAID-ON. I have switched it to ACHI and currently reinstalling Windows.

I did check for any bandwidth setting but the Dell bios doesn't appear to have anything to change it.

lumencreative · 29 Mar 2021 at 11:17

Have got it up to 1385MB/s by switching to AHCI but still far less than it should be. Starting to wonder if the SSD is bad.

lumencreative · 29 Mar 2021 at 11:30

Just tried another Adata SX8200 Pro that I hadn’t yet opened. No joy with that one either.

Journey · 29 Mar 2021 at 11:47

Don't forget all of the bandwidth is shared for the PCH, so you can't run more then one disk at full speed, and they share the bandwidth with Wi-Fi/LAN, SATA, and everything else.

lumencreative · 29 Mar 2021 at 11:51

Journey said:
Don't forget all of the bandwidth is shared for the PCH, so you can't run more then one disk at full speed, and they share the bandwidth with Wi-Fi/LAN, SATA, and everything else.

Most recent test is with just one SSD installed. There’s no other drives, no WiFi, just the integrated gpu and integrated network controller.

Journey · 29 Mar 2021 at 12:03

Test it in a PCI-E to M.2 adapter in the main 16x slot. It's unlikely to be both drives, more likely a BIOS problem or configuration issue.

lumencreative · 29 Mar 2021 at 12:09

Journey said:
Test it in a PCI-E to M.2 adapter in the main 16x slot. It's unlikely to be both drives, more likely a BIOS problem or configuration issue.

I’ve just found a pc with a Samsung Evo 970 in. Stuck that in and getting 3512MB/s read and 3274MB/s write. Just going to try the Adata in a different pc (the dell 7040 that the evo came out of)

lumencreative · 29 Mar 2021 at 12:19

Further update. Adata SSD is getting 2766MB/s read but only 934MB/s write in our Dell Optiplex 7040.

Journey · 29 Mar 2021 at 12:20

lumencreative said:
Further update. Adata SSD is getting 2766MB/s read but only 934MB/s write in our Dell Optiplex 7040.

Download the ADTA toolbox and update the firmware on the drives.

lumencreative · 29 Mar 2021 at 12:43

Journey said:
Download the ADTA toolbox and update the firmware on the drives.

Just tried that and it says 'No available SATA disk' and quits

Journey · 29 Mar 2021 at 12:50

That's odd, did you restart the machine? I've not had that message, but I always flash my drives on a specific machine.

lumencreative · 29 Mar 2021 at 12:59

I did. I'm going to try putting it back in the Optiplex 7080 so that it's not the boot drive.

lumencreative · 29 Mar 2021 at 14:42

I've given up. Contacted the retailer I purchased from (the rainforest place) and 'Technical Support' tried telling me that the 3500MB/s quoted in the specs is split between the read and write performance so getting the results I got in CrystalDiskMark is correct. Told them they didn't know what they were talking about and requested to return both drives for a refund.

Have ordered some WD Black SN750's instead.

tamzzy · 31 Mar 2021 at 09:16

Good choice. Don't support manufacturers that do the bait and switch.