Question of GTX 770 SLI pcie 3.0 speed

[Andychang]

Hi

Could you help me to understand why it is pcie 8x/8x when I enable SLI function, NOT pcie 16x/16x?

Thanks

 

[aznricepuff]

It probably has to do with how many PCI-e lanes your motherboard/chipset can support. For example most Intel chipsets (with the exception of X79) can only support 16 PCI-e 2.0/3.0 lanes. So when you have two cards plugged in, they have to run in x8/x8 since running in x16/x16 would require more lanes than the chipset can support.

Don't worry about this, though. In practice you will never saturate PCI-e 3.0 x8 bandwidth with dual-770 SLI.

 

[Andychang]

It probably has to do with how many PCI-e lanes your motherboard/chipset can support. For example most Intel chipsets (with the exception of X79) can only support 16 PCI-e 2.0/3.0 lanes. So when you have two cards plugged in, they have to run in x8/x8 since running in x16/x16 would require more lanes than the chipset can support.

Don't worry about this, though. In practice you will never saturate PCI-e 3.0 x8 bandwidth with dual-770 SLI.

Thank you. My mother board ASUS Maximus V formular, support Nvidia 2 way SLI and AMD 3 way cross fire. Does this board do not have enough lane for 2 x pcei 3.0 ?

Thanks

 

[huilun02]

It runs at dual x8 lanes at 3.0 with 2 cards installed.

 

[Andychang]

It runs at dual x8 lanes at 3.0 with 2 cards installed.

Thanks, you mean all the 2-Way SLI is running like this? how about 3-way or 4-way SLI? should be PCIe 4X?

 

[huilun02]

Like aznricepuff said, there are boards that can run at dual x16. But the majority of boards (including yours) run at dual x8 with two cards, and x8/x4/x4 with three cards. Four cards is stupid, and there is no four-way SLI unless you use two GTX 690 which contain two GPU running in SLI on a single card.

 

[Andychang]

Like aznricepuff said, there are boards that can run at dual x16. But the majority of boards (including yours) run at dual x8 with two cards, and x8/x4/x4 with three cards. Four cards is stupid, and there is no four-way SLI unless you use two GTX 690 which contain two GPU running in SLI on a single card.

Hi GTX TITAN has 4 way SLI
http://www.youtube.com/watch?v=3vCrblKzKaM

 

[huilun02]

Man that's one expensive heater.