How Does PCIE handle dual GPU's on single card.

[pezy]

I have been thinking about this recently but can't draw any conclusions, certain PCIE slots are hard wired 16x or 8x and they change depending on what slots are in use but if you are running a dual GPU card in a 16x slot is it really used as a 16 x or does it shift down to 8 x in the slot?

 

[Whiskers]

The slot will run at 16x (unless there is another slot occupied) and the lanes for the two GPUs are managed by a PLX chip on the graphics card itself.

 

[vorticalbox]

The slot will run at 16x (unless there is another slot occupied) and the lanes for the two GPUs are managed by a PLX chip on the graphics card itself.

so the slot is x16, does that mean the chip with split it x8 for the gpus?

 

[NeverBackDown]

When a single card is being used the PCIE lanes in the CPU allow for that card to use the full x16 bandwidth. When 2 cards are put into use, the PCIE lanes split into x8 x8 instead of x16. Reason being is that for Intel CPUs(going off your sig) they only have x16 lanes dedicated for PCIE. So in order for both cards to work it splits it evenly.

 

[pezy]

Ok you answered it the first time for me, thanks a bunch!