Do other PCI devices affect GPU performance?

[Joni_78]

Does anyone know if other PCI devices slow down GPU in any way these days? At some point in the past I think there were some problems that the GPU would not run at correct PCIe speed or something.

I have X570 Taichi and RTX 3060 TI. I was thinking of upgrading my firewire cable tuners with this PCI card which has four cable tuners in one card.

https://www.digital-devices.eu/shop/en/TV-Cards/All-TV-Cards/341/Digital-Devices-Max-M4-4x-Multi-Band-Tuner-TV-Card

[Steven P. Administrators]

You basically need to check your motherboard manual to see if the X16 lane shares with any other slots.

Sometimes it does, sometimes it doesn't. For example the main X16 lane always shares with the second GPU slot (X8 lane) if it is used, making them both X8.

SATA ports also share with NVMe lanes, so if you have a NVMe and a SATA drive sharing a lane, then the drive speeds will be half of what it normally is.

It is why I always check now, not all of the slots are independent of each other.

[Joni_78]

On 10/12/2023 at 14:27, Steven P. said:

You basically need to check your motherboard manual to see if the X16 lane shares with any other slots.

Sometimes it does, sometimes it doesn't. For example the main X16 lane always shares with the second GPU slot (X8 lane) if it is used, making them both X8.

SATA ports also share with NVMe lanes, so if you have a NVMe and a SATA drive sharing a lane, then the drive speeds will be half of what it normally is.

It is why I always check now, not all of the slots are independent of each other.

Thanks I'll check. If it is shared would 8x vs 16x make any difference with RTX 3060 TI?

[Joni_78]

According to manual there is some difference on PCI speeds depending from CPU and it does not say anything about 5950x (Vermeer).

 

PCIE1 PCIE3 PCIE5

Ryzen Series CPUs (Matisse)
Gen4x8 Gen4x8 Gen4x4

Ryzen Series CPUs (Pinnacle Ridge)
Gen3x8 Gen3x8 Gen4x4

PCIe slots:
PCIE1 (PCIe 4.0 x16 slot) is used for PCI Express x16 lane width graphics cards.
PCIE2 (PCIe 4.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE3 (PCIe 4.0 x16 slot) is used for PCI Express x8 lane width graphics cards.
PCIE4 (PCIe 4.0 x1 slot) is used for PCI Express x1 lane width cards.
PCIE5 (PCIe 4.0 x16 slot) is used for PCI Express x4 lane width graphics cards.

[Jim K Global Moderator]

Your 3 PCIe x16 are x16/x0/x0 or x8/x8/x0 or x8/x4/x4.  But you aren't going to be plugging that card into a x16 slot.  Assuming your two x1 slots are free and clear, you'll be using one of them and they don't appear to share anything.

[Joni_78]

Thanks.

[Jim K Global Moderator]

On 10/12/2023 at 06:54, Joni_78 said:

If I understood this right it has 3x PCI Express 4.0 x16 and those are shared. So adding that tuner into any of these it then runs at 8x.

3 x PCI Express 4.0 x16 Slots (PCIE1/PCIE3/PCIE5: single
at x16 (PCIE1); dual at x8 (PCIE1) / x8 (PCIE3); triple at x8
(PCIE1) / x8 (PCIE3) / x4 (PCIE5))*

Correct...but why would you do that ... unless your x1 slots are occupied?

[Joni_78]

On 10/12/2023 at 14:56, Jim K said:

Correct...but why would you do that ... unless your x1 slots are occupied?

Nm. Yeah you are correct it goes into x1 slot. Specifications are in German so I somehow thought this means that you need 1x free x16 slot for this

"ein freier PCIe Steckplatz (x1 bis x16)"

But yeah thank you all. x16 is shared but adding anything to x1 slots does not have an effect to x16 slots.

[Jim K Global Moderator]

Yeah, just means you can plug it into x1 or x16 ... as with any x1 card.  You can even plug a x16 card into some x1 slots ... as long as they aren't closed at the end (like yours, so you couldn't do that).  But anyway....