Will pci x8 bottleneck SLI/CFX?

tutstuts

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Dec 7, 2011
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Hey guys, I have a GIGABYTE GA-Z68A-D3H-B3 Mobo ( http://www.newegg.ca/Product/Produ [...] 6813128502 ) and right now I'm using an eVGA GTX 570 HD on the first slot (x16).

I'm wondering, am I going to lose performance (comparing to a Mobo with dual x16 slots) if I get a second card in SLI mode?

Ok, I just saw this video while typing this: http://www.youtube.com/watch?v=NFMzRZqFh-w

What I get from this is: If I put a 2nd videocard on the x8 slot, it will make both of them work as a x8, right? But even though, there is almost no performance loss at all (with GTX 580's).

Thing is, I might be stupid enough to buy two HD 7970 when they come out in January, and they are somewhat more powerful than the GTX 580's in the video. Would I have a have a bigger loss or about the same?

Thanks!
 
You will not notice any performance loss by having two cards oreating at x8 , it is done all the time and motherboards are built to operate that way. You can even put a video card in a full length slot that is x4 and you may notice a loss but not by much. The x8 SLI is unnoticable by the human eye you have to use equipment to measure it. So it not a big deal and the only way out of it is to get an expensive board that has two full x16 slots available.
The loss is a percentage so if the 7970 was 15% better than a 580 and a 580 had a 5% loss then the 7970 would have a 6 or 7% loss , again you will not notice the extra 1 or 2 %.