Sign in with
Sign up | Sign in
Your question

Diffrence between x16 and x8

Last response: in Graphics & Displays
July 15, 2010 1:37:05 PM

hi guys

i m currently using an xfx 750i its an sli mobo

it has two x8 lanes (in sli mode)

so will i experience a high or low performance decrease

your support will be well apricated

P.S thinking to sli gtx 460 or else

just add another 8800gt

More about : diffrence x16

a b U Graphics card
July 15, 2010 1:43:24 PM

The PCI-E controller will only have so many lanes connecting to the devices. The maximum amount of lanes any one PCI-E peripheral can have is 16 (x16). A single graphics card is x16 capable and will take up the full 16 lanes for maximum bandwidth.

Two graphics cards will have to share 16 lanes between them, hence x8,x8, despite the reduced bandwidth the processing power of 2 graphics cards improves performance.

Two 460's in SLI would kick ass.
July 15, 2010 1:52:52 PM

for example a guy is having 60 FPS on some game in sli of gtx 460 on full x16 x16 lanes

so how much will i get (x8 x8 lanes)
Related resources
a b U Graphics card
July 15, 2010 1:59:21 PM

Not as many as 60 because x8x8 allows less bandwidth than full x16x16 but tbh, only managing 60fps with SLI 480's... he must have seriously high res or a huge bottleneck somewhere...
a b U Graphics card
July 15, 2010 2:10:25 PM

the x8 links will not decrease performance that much, 2 x 5870's in x8/x8 link loses about 4% of the performance of x16/x16. The only cards to be affected greatly are the dual gpu cards (as each gpu is only getting x8/x8 in one x16 slot so x8 would become x4/x4)

Best solution

a c 125 U Graphics card
July 15, 2010 2:12:44 PM

8x is about 4% worse.


example from article:
July 15, 2010 7:32:06 PM

seems like i dont need to worry then
there will be a small difference although if u r getting 50 fps on x16 x16 lanes
u will get 48 or maybe 45
there is not much detectable difference between 48 and 50
thnx for the support
July 15, 2010 7:32:31 PM

Best answer selected by IROC_69.
a c 125 U Graphics card
July 15, 2010 7:40:23 PM

Yeah glad to help.

I had a little convo in another thread about it. Looks like it really depends on the GPU. Some midrange ones you won't see any difference. The only reason the 5870 is 4% faster on a 16x lane is that it's total output is just 4% more than an 8x lane can deal with. Possibly a 5970 would see closer to, oh, 10 or 15% drop in performance. But then going the other way, a 5770 might not see any change.
a c 271 U Graphics card
July 16, 2010 12:48:08 AM

This topic has been closed by Mousemonkey