Hi I am still looking for the best suitable build for myself. And still have not found the perfect one.
I am now in the situation on planning to buy a ati 5770 GPU for by build. Later upgrading the system by adding two extra cards. I have seen really good CF scalings for this situation.
However I though the i7 860 or i5 750 would be the best bang for the buck at the moment. But as you know only supports tri-fire as 8x 4x 4x. But the Amd x4 955 supports 16x 8x 8x, but is obviously a slower processor.
Which of these options would be the better one:
Intel with a fast processor and slower gpu's?
Amd with a slower CPU but faster gpu's?
If I were you I'd go for the Core i5 and only ever have a maximum of 2 cards, Tri-fire doesn't scale that well, You'd be looking at about 20% increase from 2 cards. 2 5770's on a P55 platform will give you x8/x8 which is plenty for HD5770's.
Then again at the end of the day it doesn't matter to much, a phenom II 955 and a Core i5 750 are pretty close in performance and price. So flip a coin eh?
I suggest you to go only with one card w/ a P55 build. This is the best option for this platform, but XFX/SLI performance are decent (bootleneck because of the 2x PCI-E 8x). Performance at tri GPU are horrible. If my memory is good, it's like over 20% performance difference comparated to a X58 platform.
I think that if you are ready to spend for three cards, you should be able to spend for a better single one. It's not really a good long term upgrade to put a second GPU.
I agree that tri-frie won't scale up very well. I also agree that i5s are better for gaming. That said, the 955 is almost $50 cheaper on Newegg, and and AM3 platform has a better upgrade path.
I'm also of the opinion that if you're not Crossfiring right away, there is no point in doing it. The GPU you want will be so far outclassed when you go to upgrade, it will be better just to replace a single card.
That said, if you're set on Crossfiring, the only thing you should be looking for is a 16x/16x. If you're absolutely set on wasting money on a tri-fire, obviously the 16x/8x/8x is better. The CPUs aren't so different that one will bottleneck the GPU. If that were true, no one would be building with AMD.
All of this also depends on the games you're playing. If you're playing games like Crysis, you don't need to worry too much about the difference in CPUs. Other games may be less intensive on graphics, but more intensive on the CPU.
yes , i have an i5 750 , with ud2 mobo . earlier i was considering ud4p for CF/SLI , one 5770 and one later , but then realized i would pay more amount than a single 5850 , and it would be easier on the psu , and best of all i saved 60+ dollars on the mobo with only one pcie 2.0 x16 gpu slot .
the ud2 has great overclocking support , and can be oc'ed to 4.0 (20x200) , i have an antec 300 for good airflow already . and the i5 has nehalem-class performance .
that being said , the performance at stock is enough for me now in all games . i will oc it when the cpu becomes a bottleneck for even 60 fps .
also , i considered 2 x 5770 , later 5850/5870 , but since it is not available here , i am re-using my old gtx260 for now and waiting for nvidia to come up with something in this range .
You don't need a board/CPU that can give you x16/x16 when you considering HD5770's in crossfire
A 5770 will not need more than x8 bandwidth, so it certainly will not take advantage of a x16 lane.
Really its up to you, but i agree that if you are willing to buy 2/3 HD5770's then go with a 5850/5870 for better overall performance/less heat/less power draw/less money.