Crossfire question

[into9rod]

So i got a 7770 vapor X Sapphire and i want a second card to crossfire, i been checking some benchmarks and i see that it can outperform the 6870 in most of the cases, from my point of view is like playing with a new toy at a very competitive price, i think it will be fun , my question is should i crossfire even if my pci express in my mobo is 16x-4x mode, or it will be a pain in the ass.

ty

 

[JJ1217]

You'll definitely lose performance. You typically want (When crossfiring) for lanes to be operating at x16/x8 or x8/8.

 

[amuffin]

7770 doesn't outperform the 6870....
http://www.techpowerup.com/reviews/Sapphire/HD_7770_Vapor-X/28.html

 

[dudewitbow]

ideally you would like 8x/8x. by doing 16x/4x i would think the 4x would lose about ~6% performance on a 4x slot

look at the 7970 for example when under 4x as a standalone card:

@above, i agree it doesnt outperform the 6870, but with the 12.11 changes, it definately now surpasses the 6850 and is probably somewhere between the 2 in performance, at a lower power consumption(albeit smaller bus)

 

[Guest]

ideally you would like 8x/8x. by doing 16x/4x i would think the 4x would lose about ~6% performance on a 4x slot

look at the 7970 for example when under 4x as a standalone card:
http://tpucdn.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/images/perfrel.gif

@above, i agree it doesnt outperform the 6870, but with the 12.11 changes, it definately now surpasses the 6850 and is probably somewhere between the 2 in performance, at a lower power consumption(albeit smaller bus)

you beat me to it, i was going for that benchmark, saw your post and stopped.

what i was going to add was "how much of a difference is ~6%?"

if you use 60 fps then 6% would be 3.6 fps less or 56.4.

noticeable?

 

[unksol]

you might lose a tiny bit, but it's only a 7770. If it's pcie 3.0 x4 you won't lose anything.

You'd have been much better off just buying a 7850 or 7870 to start

 

[into9rod]

Thanks for the replies, i have right now a 4870, that is almost dead, i been with this card 6 years, and at least 1 7770 vapor x is better than y old 4870, and if i add another 7770 later i will prolly have better performance, my resolution is 1680 * 1050

And i have watched some videos the 7770 vapor x in crossfire outperforms the 6870.
http://www.youtube.com/watch?v=L3E4YhRvoQY

 

[blazorthon]

Guys, you're mistaking the 7770 and the 7770 Vapor-X which is a good ~15-20% faster than a reference 7770. The Vapor-X, with current drivers, might be able to edge out the 6870. I guarantee that two 7770s in CF beat a 6870 greatly in almost all gaming performance comparisons.

 

[garrettk4]

@blazorthon look at amuffins link it has graphs with the 7770 vapor x being out performed by the 6870...

 

[blazorthon]

@blazorthon look at amuffins link it has graphs with the 7770 vapor x being out performed by the 6870...

Look at the driver version in that link. Honestly, I don't think that the Vapor-X will edge out the 6870 overall, but with current drivers, it can in some games.