PCI Express / 1156

[banja]

Howdy.

I believe the 1156 chipset reduces the pci express lanes to half (8+8) when two gfx cards are used. However, are the lanes also halved if you use any combination of two pcie cards, ie a gfx card + soundcard?

Thanks

 

[mattyfez]

As far as I'm aware, its only an issue when running two pcie graphics cards.

 

[banja]

Thanks

 

[afro]

just to add ;D

i think the performance decrease is about 1-2%

also, its also better to have 1 excellent graphics card, than 2 good, as they never scale up as well, i.e if you have 2x 5850s it wont get double the performance over 1x 5850 its something like 20-60% or something like that.

 

[wilko49]

not quite true afro, 2 5770s are a good alternative to a 5870, they pull about the same performance at a slightly lower cost (when the drivers work, at least).

everything else is right though

 

[Ordokai]

The reduced PCIe lane bandwidth performance hit is negligible in most cases, certainly nowhere near significant enough to discourage crossfire. Also scaling is rather good as of late, most combinations scale in the rage of 50-75% by adding a second card, the 20%+ figure is rubbish outside tri/quad-fire.



- Ordokai

 

[Marine-RX179]

Howdy.

I believe the 1156 chipset reduces the pci express lanes to half (8+8) when two gfx cards are used.

Not true. Majority of the 1156 boards are x16/x4. There's only minority of 1156 boards that are x16/x8 and can support Crossfire/SLI of graphic cards in x8/x8 mode.

And no, sound card won't affect the PCI-lane of the graphic card.

 

[adrichardson81]

Actually any 1156 board is 16x/4x. 16 lanes come from the CPU and 4 come from the P55. The exact options depend on your mobo.

SLI capable boards usually have 1 16/8x slot, 1 8x slot and a mixture of 1/4x slots. (If you're using 2 graphics card, both cards run at 8x)

It can be more of a lottery if the mobo's not SLI certified, as one of the 16x slots may actually be 4x slot dressed up as a 16x slot...

The lane sharing gets a bit confusing. On mine, the 1x and 4x slots share lanes, so I can have 3 slots running at 1x or 1 slot running at 4x. The top 16x slot runs at 16/8 and the 2nd runs at 8x only. Problem is the USB3 and SATA3 controllers need 8 lanes if they're enabled, which disables the 8x slot and drops the main slot down to 8x too.

To go back to your original post, as long as you put your sound card in a 1x or 4x slot, it won't affect your graphics card.

 

[banja]

Good info. Thankyness.