Would my mobo destroy Crossfire performance?

[ElliottJames]

Got a Gigabyte h55m

I heard because it only has one pce-i x16 slot and another x4 for crossfire support, I won't be getting optimised performance.

The thing is I'm tight on funds and I can afford another 6950 to go into my current setup. The only problem would be I could only upgrade the motherboard in a few months

Would it seriously affect performance? To the point of it being a waste of money, or only marginally? Please honest answers as I need to purchase a second as I've got a deal of a mate.

 

[Surveyor]

The average reduction in performance is around 10% running at x16/x4 compared to x8/x8.

Individual games vary from pretty much no difference to around 25% loss of performance.

Does CrossFire Work At x16/x4?

Also does your case have enough expansion slots on the rear to add a second card and do you have a powerful enough PSU?

 

[ElliottJames]

600W Psu but I can upgrade easily to something sub £80

And yeah I have a big case I hope, PCk58 LAncool

 

[RJC]

PSU on offer this week, unitll next Wednesday:

http://www.overclockers.co.uk/showproduct.php?prodid=CA-004-XF&groupid=701&catid=123&subcat=1497

 

[Orcvader]

Does the H55 chipset even support Crossfire?

 

[RJC]

Thought I have a quick look, link below shows the board having crossfire support (board linked only, not sure on op model.)

http://www.gigabyte.com/products/product-page.aspx?pid=3572#sp

 

[ElliottJames]

Yeah it does support Crossfire but I'll get a new motherboard I guess

 

[MOOGLEYS]

I'm just trying a second 6950 in my 4x slot just to see what difference it makes. I have only had a quick go so far but it seems to work ok. The 3d mark 11 score is almost double that of a single card and according to fraps my BF3 min fps is 55 before it was dropping to around 30.
I'm also amazed my 550W ocz fatality psu seems to be happily powering both cards with no increase in fan noise..
I have had crossfire 6950's before on an nvidia am3 chipset running dual 16x and in all honesty I did not really notice a great deal of ingame benefit but this was when the 6950 was first released.

 

[Deleted member 115712]

If you are worried about the difference between 16x and 4x watch this video.

 

[MOOGLEYS]

If you are worried about the difference between 16x and 4x watch this video.

Considering that is a 6990 dual 6970's running in a x4 slot a 30% decrease is not bad at all.
No wonder my 6950 in a x4 slot seems to work fine..

Nice Vid

 

[ElliottJames]

Hey Moogleys, how's the Crossfire going performance wise? Looking to get a cheap 6950/70 when everyone puts them on the MM for the new cards release. Would I notice a performance increase @ 2560x1440?

 

[MOOGLEYS]

Hey Moogleys, how's the Crossfire going performance wise? Looking to get a cheap 6950/70 when everyone puts them on the MM for the new cards release. Would I notice a performance increase @ 2560x1440?

I only have 1080p mate so not sure. It worked fine though in all honesty I had crossfire 6950's in one of my previous pc's running with a 4ghz 955 on an nvidia chipset board that had dual 16x pci-e and this seems to be identical in performance with 16x/4x...
I'm having to get the 2nd card back in the i5 system I just built as it's being collected tomorrow but I think you should see a nice improvement in games that support crossfire.