Crossfire or not?

[Widowmaker5000]

I recently purchased an evga x58 sli le motherboard and decided to put a Radeon 5770 in it. Compared to the PS3 in high def I am pleased with the results. However, I would like to put another 5000 series card for crossfire capability but how can I when the back of the video card takes up two slots on the back of my tower? It also concerns me to see how wide the 5770 is, the fan covers the pci-e audio slot and goes all the way to the next pci-e slot. If i baught a 5800 or 5900 series does anyone know if these cards would work together? Are they to wide?? And how could they work together if the rear of the card takes up two tower slots??? My mobo did come with an extra long sli connector for three way sli, would that work since it has an Nvidea logo? Also, would it work if the middle port was left empty?(for spacing)

 

[Daedalus685]

I'm not sure if the 5800s will work in crossfire with a 5770, but it will be worthless in any regard anyway... though I'd imagine it would "function". Crossfire will only be as fast as the slowest card in crossfire, regardless of the faster card in the pairing.

As for the spacing, yeah.. modern cards take u[p two slots and there is little that can be done bout it. Your motherboard has plenty of slots to accommodate crossfire/SLI but you will lose availability of a couple of the other slots. You will need a large enough case obviously as well.. With that MB crossfire will mean covering the x1 and pci slots. If you need the pci you can probably run crossfire from one of the lower pcie slots if you have an extra long crossfire bridge (though it might be at a slower connection speed, I'm not sure on the exact specs)

 

[TJ Tom]

Your board has 4 PCI-e slots? You should have more than enough room. I think a 58xx CAN work together with a HD57XX card because a HD5970 can work together with a HD5850. Normally I would tell you not to buy a HD5800 series card to go with your card but I recently read a review in wich the performance of a single HD5970 was dubbeled when they added a HD5850!

I don't know how legit that review is but I don't think he faked the benchies. Search for Oddfire- trifire or HD5970 HD5850 and you should find some reviews about this "oddfire" so I think HD5770 + HD5850 might be interesting.

 

[TJ Tom]

Probably totally off-topic but really interesting, seeing HD5970 quadfire doesn't come close to HD5970 + HD5850.

 

[Daedalus685]

A 5970 + 5850 works fine as the GPU's in 5970 are running at near enough the same speed as that in a 5850. With a 5770 compared to a 5850/70 that is not the case.

Given that crossfire works asynchronously it is possible drivers may have improved to split the work load up in a way that is not 50/50 to improve mixed crossfire scaling (such that a lesser card with a great card does not result in less performance than the great card on its own) but I'm not aware of any changes in this, and would not ever expect them.

Edit: It is quite interesting to see just how well tri crossfire scales.. I wonder if they did indeed put in optimizations for mixed crossfire (it would be very handy for the 5970 as it is not a true doubling of the 5870 as the 4870x2 was) or if quad crossfire really just scales that much worse than triple. Mind you, I can't see those 5970+5850 benchmarks at work, were they done at different settings than the average 5970 quadfire review?

 

[TJ Tom]

My reply was based on that review in wich I see Heaven benchmark and crysis benchmark results at Full HD resolution and 8 times AA and I'm comparing those to HD5970 quadfire benchies I have sene on the web and on Youtube (might search for efaco5's youtube channel). His scores at 1680x1050 (no AA) are lower than the tri fire scores at Full HD and 8xAA. As far as drivers are concerned I don't know which drivers they used etc.

All in all I find the benchmark review a little awkward and I would love to see anandtech or Guru3D or anyone do a review on Quadfire vs Trifire.

HD5970 vs HD5970 quadfire vs HD5970 + HD5850

It's hard to find benchmarks comparing those or even HD5870 crossfire vs HD5850 crossfire or HD5850 crossfire vs HD5970 etc. I still wait for a reviewer to come up with a nice chart!

And I forgot the 57xx series are clocked at toally different clocks, oops.

 

[Widowmaker5000]

My 5770 came with a crossfire connctor but how do they expect anybody to be able to use it when it only spans two slots?? Also my mobo came with a two way and extra long three way sli connector. But it has an Nvidea logo... would that be compatable? And would it work with an empty middle port.

 

[Daedalus685]

You can't use an SLI bridge for crossfire, they are different connections.

All crossfire bridges are designed to be long enough to reach over a slot in between, as almost all cards are double slot, and even more MB's have something between the primary PCIe slots. If you are trying to crossfire between slots that might be spaced 3 or more apart you will need to buy a longer bridge.

 

[Widowmaker5000]

Its nice to know that I stand corrected about the crossfire bridge. I took a closer look at it and it looks long enough to span a couple slots if needed