PCI-E16X cards on PCI-E8X port

[2017davidwade]

As about what are the affects of using a GPU that's PCI-E 16X 3.0 on a PCI-E 8x Socket. My board had a

PCI-E X16 2.1
PCI-E X8 2.0 and a
PCI-E X4 2.0. So if my card is a PCI-E X16 3.0 what do I lose on a 2.1 socket then add a second card twins with SLI. They are 144.2gbs per seconds. My board says using two sockets two cards make them 8x speed each. Would I lose thoughput

 

[icraft]

You would lose a few percent at most. 2.0 x8 is the same as 3.0x4 which is still ok for basically all cards. I have to ask why you're using SLI though, not many games even support it anymore, and the ones that do can be glitchy.

 

[2017davidwade]

Just wondering that's all. Using one at 16x 2.1 the card is a 3.0 16x. Full speed. Using a second would drop a little both sockets would run at 8x 2.0. So its2 nice the know that would. I have two EVGA 2GB GTX 660ti SC 1.1ghz core 1,600 memory. Only for GTA5

 

[Barty1884]

Roughly speaking, x8(Gen3) = x16(Gen2), with Gen2 x8 (which you'd be for SLI) = (+/-) Gen3 x4 in terms of bandwidth.

Performance will very likely be impacted (by how much will likely vary title to title).

Considering SLI requires a minimum of Gen3 x8 (in terms of bandwidth), I'd expect some pretty substantial performance drops more often than not.