running x16/x4

[Noah1142]

hey guys i have this motherboard http://www.overclockers.co.uk/showproduct.php?prodid=MB-391-GI

i also have a Gigabyte X3 Windforce 7950, an i was planning on getting crossfire,
unfortunately my motherboard only supports x16 and x4 pcie speeds - my question is : will crossfire be any different compard to a x8/x8 or x16/x16?

thanks

 

[IxD3ViiLx]

no

 

[JamieH]

Depending on which games you play you may only see a small difference between x8/x8 compared with x16/x4. Some games scale similar with about ~10% reduction in x16/x4

That said I have this mobo and thought about CrossfireX. I was going to put to 7950s in it but decided it would be best to just use a single card and upgrade the mobo if I wanted to use multiple GPUs.

 

[Surveyor]

The answer is hardly a simple no.

Does CrossFire Work At x16/x4?

A test from a while ago with HD 6950s.

Some games were hardly affected while others lost up to 25% performance.

I guess you'd see a similar range of results today with different games and HD 7950s.

 

[Uncle Petey]

I very briefly tried this with a couple of 7970's on my x16/x4 mobo recently, and yes, results were mixed.
I don't have a full breakdown as I only toyed with it for less than an hour.

BF3 loved it and was running at around 120-140fps odd most of the time.
F1 2012 didn't like it and performed worse than with a single card on the benchmark. Single card> Min-91 Max-111. Dual cards> Min 67 Max 81.
Batman AC averaged 103fps which is an improvement over a single card, but I can't remember what those scores were
Heaven benches really liked it

Sorry I can't give you more detail or proper testing results. It was just a quick blast.

 

[tommybhoy]

^
As petey found out, it's game dependent.

The answer is hardly a simple no.

Does CrossFire Work At x16/x4?

A test from a while ago with HD 6950s.

Some games were hardly affected while others lost up to 25% performance.

I left out the last line due to the higher/mem bus/grunt of the 79's v's 69's, causing a bigger bottleneck, it will be higher than 25%.

 

[LtMatt]

I used to run x16 x4 xfire on a 6950 setup. The difference in performance was 5-15%. Its not ideal to be honest, but it will work and improve your fps. As tommy says expect a bigger % hold back with faster cards. It will make do for now, but you really need a x8 x8 motherboard in the long run or its just a waste.

 

[Rusty0611]

I used to run x16 x4 xfire on a 6950 setup. The difference in performance was 5-15%. Its not ideal to be honest, but it will work and improve your fps. As tommy says expect a bigger % hold back with faster cards. It will make do for now, but you really need a x8 x8 motherboard in the long run or its just a waste.

+1