How much slower is a x4 lane?

[jeb1517]

I have a e-VGA 7900GS video card installed in a motherboard that only has a PCI-e x4 lane (not x16). How much will this hurt my performance? Like, is it 1/4 as fast or what?

Computer:
e-VGA 7900GS 256MB VC
pentium d805 2.66GHz
ASRock 880 dual pro mobo
corsair tiwn x 2 x 1gb
maxtor pata 60gb hdd

 

[blade85]

for a 7900GS....im guessing a performance loss of less that 5% (in games)

Here is a scaling test done on this site a few months back: http://www.tomshardware.co.uk/pci-express-scaling-analysis-uk,review-2125.html

Im guessing its just the 8800 cards (and now the HD2900 cards) that make a fairly big difference in terms of 4x and 16x.

 

[raytracer06]

I have a 8600GTS, and I recetly replaced my Asrock 775 Dual-VSTA with a MSI P35 Platinum. I tried a few games and 3dmark05/06. PCI-E x4 was 10-15% slower. Of course, the more powerful your card is, the more it will be likely to be bottlenecked, but a 7900GS should be fine.

I also noticed that a few video issues disappeared since I switched to a x16 PCI-E port : corrupted polygons in some games, and sometimes random crashes during video playback/edition. seems the 8600gts doesn't like to run on PCI-E x4

 

[Hatman]

Shouldn't give any NOTICEABLE decline in performance.