One card, faster than Crossfire

[exile26]

Hi guys

Currently im running a i5 750, OCZ Reaper ram, Asus P7P55D Mobo with HIS 5770 Cards in Crossfire. Im not satisfied with the perfomance, i've noticed that on some games its got the same performance with 1 card than on CF. My drivers and app profiles are up to date. The motherboard PCI lanes run at 2.0 x single 16 and 2.0 x single 16 @ 4. Are there 2.0 x 16 pci-e mobo's abailable than run @ 16 IN both lanes or do they only come in 2.0 x 16 @ 4 and 2.0 x 16 @ 8. Please give me some advice and some models if u can.

 

[Maziar]

On PCI-E 2.0 boards,you won't notice a huge difference between dual x16 and x16x4.
Can you explain more about your performance ? how's your FPS in games ? and what are your other system specs ?
Finally what resolution do you play at ?

 

[exile26]

But isnt 16@4 suffocating the other card, if the fisrt one is running @16. For example Splinter Cell Conviction, Kane and Lynch Dog days, Mirrors Edge. I'm unsure about the FPS but on full graphics with anistroptic filtering and antilaliasing on the games gets like a stutter when playing. When i disconnect CF it runs smooth. The games are not so new so i im not sure that it can be the games. But on games like Mass Effect 2, Dirt2, Call of Duty(All) it runs smooth. My resolution are at 1920 x 1080. Altough when i benchmark with 3dmark 2006 it hits a 18700 score.
My System specs if it will help:

I5 750 @ 2.7Ghz
Asus P7P55D
OCZ Reaper 4GB @ 1600MHZ
2 x HIS DDR5 1GB 5770 CF
Gigabyte ODIN PSU 585W
1TB seagate HDD
24 inch Benq 1920 x 1080

 

[Maziar]

For PCI-E 1.0 boards,the difference between dual x16 and x16x4 was significant, but like I said things are different with PCI-E 2.0 boards,here is a review of GTX 480 scaling in x4x4 speed(which is even slower than x16x4)
http://www.hardocp.com/article/2010/08/25/gtx_480_sli_pcie_bandwidth_perf_x16x16_vs_x4x4/
"The results are actually a bit shocking to us to be honest. We weren’t so surprised that in the previous evaluation x8/x8 did not cause any differences at 2560x1600 but did at 5760x1200. However, we thought certainly at x4/x4 PCIe 2.0 mode there would be some kind of a bottleneck at 2560x1600, but the results have proven otherwise. Even with all the data that GTX 480 SLI is pushing across the PCIe bus, x4/x4 is NOT a bottleneck in a single display setup at 2560x1600 with AA enabled. The only game to show us any difference was AvP, but it did not affect the gameplay experience. Therefore, if you are on an aging PCIe 1.X system at x8/x8 mode (equivalent to PCIe 2.0 x4/x4) on a single display fear not, you are not holding back the performance of GTX 480 SLI or we guess with any CrossFireX or SLI configuration. "

If you're getting better performance with CF disabled,then either one of your cards isn't working well or there is a problem with your current driver.