Questions about PCI 16x and 4x

[iMove Quick]

Hi there,

So there is alot very unclear for me about the x4 and x16 slots on my motherboard.

So I have a R9 380 running in my pc now (3.0 16x slot, that's fine, I know.), but I want to put another R9 380 into my system. But when I want to that this will happen (Directly from PC store's specifications) : "When the PCI-e 2.0 x16 and PCI-e 3.0 x16 slot are being used, they both switch back to x4". So does that mean both GPU's will be running x4/x4?

My motherboard is a MSI H97 PC MATE, and it has crossfire support.

And if so, will there be a big peformance loss?

Thanks for reading!

 

[utroz]

Weird that one slot is PCI-E 3.0 and the other is PCI-E 2.0, it says it will bump them down to x4 speeds. It will work but probably cost you 10+% of performance because your cards use XDMA Crossfire so slower PCI-E speeds tend to effect them more. You would be better off getting one high end card than 2 380's..

 

[iMove Quick]

Weird that one slot is PCI-E 3.0 and the other is PCI-E 2.0, it says it will bump them down to x4 speeds. It will work but probably cost you 10+% of performance because your cards use XDMA Crossfire so slower PCI-E speeds tend to effect them more. You would be better off getting one high end card than 2 380's..

This is what the manual say's :

*2x PCIe x16 slots
- PCI_E2 supports PCIe 3.0
- PCI_E4 supports PCIe 2.0
- Support x16, x4/x4 modes
*2x PCIe 2.0 x1 slots
*2x PCI slots

 

[utroz]

Weird that one slot is PCI-E 3.0 and the other is PCI-E 2.0, it says it will bump them down to x4 speeds. It will work but probably cost you 10+% of performance because your cards use XDMA Crossfire so slower PCI-E speeds tend to effect them more. You would be better off getting one high end card than 2 380's..

This is what the manual say's :

*2x PCIe x16 slots
- PCI_E2 supports PCIe 3.0
- PCI_E4 supports PCIe 2.0
- Support x16, x4/x4 modes
*2x PCIe 2.0 x1 slots
*2x PCI slots

I read the manual as well. So what I think it means is in crossfire mode the top full length slot would be at PCI-E 3.0 x4 and the bottom full length slot would be running at PCI-E 2.0 x4 so it could bottleneck some for sure..

 

[iMove Quick]

Weird that one slot is PCI-E 3.0 and the other is PCI-E 2.0, it says it will bump them down to x4 speeds. It will work but probably cost you 10+% of performance because your cards use XDMA Crossfire so slower PCI-E speeds tend to effect them more. You would be better off getting one high end card than 2 380's..

This is what the manual say's :

*2x PCIe x16 slots
- PCI_E2 supports PCIe 3.0
- PCI_E4 supports PCIe 2.0
- Support x16, x4/x4 modes
*2x PCIe 2.0 x1 slots
*2x PCI slots

I read the manual as well. So what I think it means is in crossfire mode the top full length slot would be at PCI-E 3.0 x4 and the bottom full length slot would be running at PCI-E 2.0 x4 so it could bottleneck some for sure..

Sorry for late reply, but still give a noticable increase in peformance?

 

[utroz]

Yes you should still get a noticeable increase in performance in games that support crossfire.