6950 crossfire 16x/x4 bad?
 

So im thinking of going crossfire 6950's but the only thing that is stopping me is that my motherboard only supports 16x/x4 crossfire..so what i want to know is how much performance will i lose and is it worth it?im gaming at 1600x900 yes,yes,i know overkill..I KNOW!!

I wouldn't cross fire x16 /x 4 only x8 /x8 and above

At that low resolution, I wouldn't recommend it as a decent upgrade at all. If you plan on upping your resolution, thats a different story.
According to toms, the 6950 at x4 will get anywhere from 25 to 50% less performance then at x16, depending on resolution. What motherboard and cpu are you using?
http://www.tomshardware.com/reviews/...ce,2887-6.html

Also, make sure you board has a x16 physical slot wired for x4 electrical, and not just a x4 physical slot, otherwise the card won't fit.

You may want to check out some pcie scaling articles for further reading:
*Asus P8P67 (PCIe 16x/4x) vs. Asus P8P67 Deluxe (PCIe 8x/8x) - HD6950s in CF tested* - AnandTech Forums
GTX 480 SLI x16/x16 vs. x4/x4 - GTX 480 SLI PCIe Bandwidth Perf. - x16/x16 vs. x4/x4 | [H]ard|OCP
http://www.tomshardware.com/reviews/...x4,2696-3.html

It was bad when I tried it with 3870's years ago. (and a pair of 6800GS's long before that :whistle:)

No such thing as overkill. Using 16x/x4 for crossfire is pure stupidity.

Let me put it this way, why would you pay for 2 expensive gpu and cheap out on a board that can't bring out the cards true potential?


You probably won't lose performance depending on the game, but extremely small gain using 16x+x4 PCIE lanes.


Time to upgrade motherboard board, or go 6990.

You'll probably net better overall performance going with two lesser cards.
I would not suggest using what you want to use on a board that only offers those lanes, you would really be choking the second card.


ST

just get one 6950 and see what gives.

welcome aboard btw

[IMG]http://www.************/images/articles/1282682382IabXi1rEcG_1_4_l.gif[/IMG]
[IMG]http://www.************/images/articles/1282682382IabXi1rEcG_1_5_l.gif[/IMG]

http://www.************/article/2010/...x16x16_vs_x4x4

That is done on a X58.

Most mother board that support X16 + X4 are budget board , the X4 lane been controlled by the chipset. What good will do you by adding extra latency between cpu and gpu? A good headache from the Micro Stuttering. :rofl:


But don't take my words for it, best way to find out is to experiment. :biggrin:




A much much better scaling review.


AMD Radeon HD 5870 PCI-Express Scaling Review - Page 1/26 | techPowerUp