Performance difference PCI-Ex 16 vs -EX 8?

Basically in x8 lanes even an 8800GTX/Ultra will be barely bottlenecked (and having the greatest bandwidth, they are most likely to be restricted)
Have a look here for more info-
http://www.techspot.com/review/45-nvidia-nforce-650i-sl...
Basically my GTX's in x8 SLi are probably losing 2/3FPS at 100FPS or above.
Negligible in my opinion, especially as a 590SLi board was pretty much double the cost !

Thanks for the info; I just bought the MSI P7N Zilent with the 750i SLI chipset and Zalman NP9500 CPU cooler. It will accomodate a GeForce 9600 GT 650/1800Mhz card. The blue PCI-Ex x16 slot is situated a bit close to the CPU. I wondered if I would mess my system up by using the x8 slot.

Much appreciating your help!

Just to let others know:
My P7N 750i works absolutely great. It seems my C2D E6400 runs so much better than on P965 MoBo.
I did have to buy a new PSU: the P7N needs an 8-pin CPU ATX supply and the 9600 GT needs a 450-500W minimum supply .

I purchased the Cooler Master Real Power M620 w/ Modular cables

The Zalman 9500 cooler keeps my CPU at 22C under load. Now that is nice.