Question 980 + 970 NVMe SSDs, 980 has significantly slower write than 970 and advertised

[blastdoub1e]

So I have two M2 NVMe drives setup, a 970 Evo Plus and a 980 Evo Pro, each one is 500GB. Both are installed on a Gigabyte Aorus Elite x570. The results below were captured with the 980 in a PCIe Gen 4x4 slot, and the 970 in a PCIe Gen 3x4 slot.

CrystalDiskMark 970 Results

CrystalDiskMark 980 Results

As you can see, the 980 is much slower in write speed than the 970. Now, it does have a fuller drive, but I wouldn't expect it to be that much slower, given the advertised write speed is 5,000 MB/s. Here is the list of things I've tried:

✅ Verified write cache is on for both drives
✅ Verified drives are using AHCPI controllers (not RAID)
✅ Verified consistent results on various M2 slots on my motherboard
✅ Both drives have heatsinks installed
✅ Over provisioned both drives using Samsung Magician's recommended setting (10%)
✅ Ran chkdsk on both drives, no errors
✅ Ran trim optimizations on both drives
✅ Verified latest firmware on both drives via Samsung Magician
✅ Even checked using a M2 -> PCIe4 adapter (no significant difference in performance results)

One thing I didn't check is whether the 980 is being throttled. It does have a heatsink, so not sure this would be an issue. In any case, I'm not sure how to verify this.

Other than that, I'm not sure where to go from here. Is it possible I just have faulty hardware?

 

[popatim]

You weren't specific enough in where each drive was plugged in so I'm guessing that the 980 is in the M2B socket which is attached to the Chipset instead of the CPU so data writes have to go thru the CPU via interconnect bus thus slowing you down.

 

[blastdoub1e]

You weren't specific enough in where each drive was plugged in so I'm guessing that the 980 is in the M2B socket which is attached to the Chipset instead of the CPU so data writes have to go thru the CPU via interconnect bus thus slowing you down.

I think I mentioned this in the post, but maybe it wasn't clear:

✅ Verified consistent results on various M2 slots on my motherboard
...
✅ Even checked using a M2 -> PCIe4 adapter (no significant difference in performance results)

I've tried the drive on all of my M2 slots available, as well as used an M2 -> PCIe4 adapter card, and the results were more or less the same.

 

[popatim]

Well if you used it in the m2a slot then I'm not sure what's going on.
Can you run magician on it and secure erase it and benchmark again? All I can think of is it still needs to erase cells before it can write...

 

[blastdoub1e]

Well if you used it in the m2a slot then I'm not sure what's going on.
Can you run magician on it and secure erase it and benchmark again? All I can think of is it still needs to erase cells before it can write...

I thought this could be an option, but this would be a huge inconvenience as it is the boot/master partition. I will see if there are any other suggestions here and try out this suggestions short of anything else. Thank you for your input.

 

[Maxxify]

If you have another system to try it in (with at least x4 PCIe 3.0) then I would do that. Specifically your sequential writes (Q8T1 and Q1T1) are being hit which usually will have the Q1T1 scoring lower, so something is going on there. Be sure to test on that machine with only the 980 PRO installed also. Samsung does have a NVMe driver which you should have installed (if not, install it) - my thinking here is that the 980 PRO is a new drive that may have driver issues or, in the least, issues with multiple Samsung NVMe drives. (you can also test w/o Samsung's NVMe driver, using Microsoft's default - a fast way might be to test in safe mode if you haven't)

 

[blastdoub1e]

Looks like this might be a known issue with the 980 Pro:

Getting slow NVME write speeds

I have a Samsung 980 Pro PCI 4 drive and I did a benchmark, and Im getting good read speeds, but very slow write speeds at 1,100 mb. The drive is only 1/3 full, and its running on the PCI x4 mode as listed in the bios. I tested other NVMEs and they are working fine. SATA mode is in the BIOS...

www.techpowerup.com

Going to follow up in the thread above and circle back here if a solution is found.