Can GPUs be used in any of the 3~5 PCIe x16 slots?

[zeock9]

Do PCIe x16 slots have specified set lane assignments regardless of how many GPUs are being used at one time, ie) first one is x16, second one is x8 etc.?

I know there's a recommended guide for multiple GPUs setups depending on different manufacturers, but does the same hold true for a single GPU?

I want to move my GPU down from the top slot, closest from the memory, to a middle PCI slot due to ventilation issues, but was wondering if doing so would create a performance downgrade if I'm not supposed to do that.

Sorry about such a newbie questions!

 

[ShintaiDK]

It depends largely on the motherboard.

For a LGA15xx board you would most likely end with x8 in the second slot. The performance impact however is 0-1% with more on the 0 than 1.

 

[KaRLiToS]

It depends largely on the motherboard.

For a LGA15xx board you would most likely end with x8 in the second slot. The performance impact however is 0-1% with more on the 0 than 1.

^^This, man you are a great source of information. You have a lot of credibility to me.

Like Shintai said, it depends on the motherboard. It is also detailed in every motherboard manuals on what is the best configurations to use. But if the GPU is causing issues in the 1st slot because of the heat, I don't see any inconvenience to install it in the second slot. Even 8x will be fine.

 

[Skott]

Yeah, definitely depends on the mobo. For example on my Asus Z97 WS mobo its slot #1 and #5 for SLI/CrossFire for my 290x cards for 16x pcie. Its why I chose this mobo. Good spacing for the cards so air can get in between them for cooling.

 

[BrightCandle]

The answer is almost certainly no you can't use all the slots. Even on X79 or X99 the slots are given reduced lane counts and you have to take account of the recommended layouts and what happens when things are plugged in where.

Its one of my pet peeves about the move from PCI to PCI-E and it going onboard the CPU. With PCI you could plug cards into any free slot with space, with early PCI-E you could also do the same, the chipsets had enough lanes. But since all the lanes went onto the CPU we have been starved for lanes and the end result is a tonne of complexity when it comes to working out if you can add a card and where it can go. The simple addition of a sound card can break SLI/crossfire performance for example and that is really really bad.