New NVME Running at HALF Speed - What could be the cause?

@bobkn: My bad, I meant RTX3070 :)

Thank you for explaining it. So it sounds like Sabrent is saying that my current GPU (GTX760) uses X4 and based on what you're saying most GPUs are now X8 - is this correct?

And even so if the RTX3070 is X8, that should still work OK on my system without affecting the NVME SSDs, correct?

(The post you linked mentions however that the GPU uses the CPU lanes, not the PCIe ones...so I'm still a bit confused!)

orlando1974 said:

@bobkn: My bad, I meant RTX3070 :)

Thank you for explaining it. So it sounds like Sabrent is saying that my current GPU (GTX760) uses X4 and based on what you're saying most GPUs are now X8 - is this correct?

And even so if the RTX3070 is X8, that should still work OK on my system without affecting the NVME SSDs, correct?

As far as I know, the GTX 760 uses 16 PCI-E 3.0 lanes by default. Not that it needs the bandwidth.

I wouldn't bet my life on the number of full bandwidth PCI-E lanes that would be available to the GPU and two M.2 drives. I'm still mystified as to why the WD and Sabrent drives behaved differently. It's too bad that you haven't got past the first line of support (script readers), apparently.

Sorry that I can't reassure you. I'm just a hobbyist.

If nvme steals some lanes from the GPU slot dont be concerned, especially if its a 4.0 board.

That slot is so over provisioned it's funny.

Video cards typically are x16. The number of physical slots is obviously dependent upon the motherboard, but the total number of lanes "available" depend upon the CPU and the chipset on the motherboard.Your Intel Core i7-9700k has 16 lanes of PCIe 3.Your Z390-A chipset provides 24 lanes of PCIe 3.

The video card will get all 16 lanes provided by the CPU.
Each M2 would get 4 lanes and if using 2 M2's would use 8 lanes of your PC lanes from your chipset. Both can run at full x4 speed.

pparks1 said:

Video cards typically are x16. The number of physical slots is obviously dependent upon the motherboard, but the total number of lanes "available" depend upon the CPU and the chipset on the motherboard.Your Intel Core i7-9700k has 16 lanes of PCIe 3.Your Z390-A chipset provides 24 lanes of PCIe 3.

The video card will get all 16 lanes provided by the CPU.
Each M2 would get 4 lanes and if using 2 M2's would use 8 lanes of your PC lanes from your chipset. Both can run at full x4 speed.

Sounds pretty clear but just to confirm... based on what you wrote, which is specific to my situation - upgrading my GPU will not affect the performance of my 2 NVMe drives since the GPU will be using the 16 lanes from the CPU, not the chipset.

Did I finally understand?

orlando1974 said:

Sounds pretty clear but just to confirm... based on what you wrote, which is specific to my situation - upgrading my GPU will not affect the performance of my 2 NVMe drives since the GPU will be using the 16 lanes from the CPU, not the chipset.

Did I finally understand?

Yes, that is correct. Your video card will get full PCI Express performance as the 16 lanes are handled by the CPU.

The only "limitation" you could see is as follows

• Your motherboard chipset provides 24 lanes
• Devices running off the chipset will share the DMI 3.0 bandwidth between the chipset and the CPU. That's about 4GB/sec link.
• So, in the right storm of USB traffic, and network card traffic and NVMe traffic, you can fully saturate the DMI bandwidth between the chipset and the CPU. But that is just a momentary limit....its not like the system will set permanently a device to a slower speed. They will get full speed up until the point they cannot, and then once that bottleneck clears, they get full speed again.

Here is a picture representing my chipset setup, from an AMD Ryzen and X570 standpoint. Everything on the right has to move through that connection in the center, which provides just about 8GB/sec.

Clear, thank you!

pparks1 said:

Here is a picture representing my chipset setup, from an AMD Ryzen and X570 standpoint. Everything on the right has to move through that connection in the center, which provides just about 8GB/sec.

(snip)

The motherboard of "orlando1974" (Z390) sonly supports PCI-E 3.0, so the bandwidth will be half that of a 4.0 system. The proposed upgraded GPU will support 4.0, but not with that motherboard.

I'm still wondering about an explanation as to why a WD NVME drive runs at full speed in both M.2 slots of the motherboard, while the Sabrent drive does not. I have read that having two M.2 drives on that board should limit the bit rate of both drives (due to the limitation of the PCH controller), but that doesn't appear to have happened in practice.

@bobkn wish I could answer that. Neither Sabrent or Asus seem to be able to provide any clarification. I guess the real winner is WD, as it was without hassle in either port! Def a mental note to self! But I have to say I'm very happy with the Sabrent's performance so far, especially considering the price point. :)

While I've got you here, I wanted to ask.... I was surprised when I attempted to do a full backup of my 4TB NVME to a 4TB portable drive.... I actually ran out of space on the portable drive. Ugh, what a drag to have to put the remainder on a different drive. Is it common for drives to have the same advertised SIZE (ie. 4TB) but have different amounts of actual available space on them? The Sabrent's actual capacity indicates 3.72TB, my internal HDD 3.63TB, and my portable 3.63TB. So it seems like the NVME is a bit more generous...