TriFI 5870+5970 confirmed

l88bastard

l88bastard

2[H]4U
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Ok even though new egg sent me a broken 5970 (its fan sounded busted and it was artifacting badly) I was able to confirm that yes you can indeed Crossfire a 5870 and a 5970 (you just gotta match the clocks up). So everybody that was wondering, wonder no more.

As for me, I will be waiting for my replacement 5970 :(
 
Interesting. I'm just curious, IIRC NV cards take the lower speed automatically when you SLI two cards with differing clock speeds. The ATI cards don't do this?
 
J3RK said:
Interesting. I'm just curious, IIRC NV cards take the lower speed automatically when you SLI two cards with differing clock speeds. The ATI cards don't do this?
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No, each card can run its own clock and memory speed. Each card can run a different fan speed as well
 
Exeodus said:
No, each card can run its own clock and memory speed. Each card can run a different fan speed as well
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no.

Just like with different memory capacities..different clock speeds will result in the lowest common factor being used.

Eg: 700/1200 with 900/1200 the 900/1200 will downclock to 700/1200. Unless you manually overclock the 700 to 900.
 
That would make the most sense.

I haven't used dual ATI cards other than a pair of matched 4850s that I had briefly until I replaced them with GTX-280s at the time. I've read a few threads today where "making sure the clock speeds matched" was mentioned, so I thought I'd find out. (I usually buy matching cards anyway, but sometimes it's just easier to get a fairly close card due to availability (like SLIing EVGA cards where they release the same card with slight clock bump every couple of months.)
 
risqu3 said:
no.

Just like with different memory capacities..different clock speeds will result in the lowest common factor being used.

Eg: 700/1200 with 900/1200 the 900/1200 will downclock to 700/1200. Unless you manually overclock the 700 to 900.
Click to expand...

This is exactly what it does. I had my 5970 in the primary slot and the 5870 in the secondary slot and it down clocked the 5870 automatically.
 
just overclock the 5970 to the 5870 speeds.. brent already showed it can easy run them.. then ya dont have to worry about any cards being downclocked..

but good to know they do work in tri-fire..
 
sirmonkey1985 said:
just overclock the 5970 to the 5870 speeds.. brent already showed it can easy run them.. then ya dont have to worry about any cards being downclocked..

but good to know they do work in tri-fire..
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I'm not sure how well this will work in practice though. The 5970 was already having problems running overclocked in some reviews, with it easily hitting 100c and then having the speeds throttled. With the card being completely flat such that the fan is totally blocked when using crossfire, it would be crazy to try to overclock in crossfire without watercooling. s

Some cards have indentations so that the fans can still breathe even when the cards sit flush in multi gpu setups. Not sure why ATI went with the totally flat design here. Also, the 5870 is a little shorter than the 5970, but still long enough to block the fan.
 
I have 1 5970 and 2 5870's in quadfire right now.. working great for benchmarks so far other then the fact that you cant set the 5970 clock speed over 1000.. :( bummer..
 
l88bastard said:
Ok even though new egg sent me a broken 5970 (its fan sounded busted and it was artifacting badly) I was able to confirm that yes you can indeed Crossfire a 5870 and a 5970 (you just gotta match the clocks up). So everybody that was wondering, wonder no more.

As for me, I will be waiting for my replacement 5970 :(
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You might end up with just a cash refund. Newegg tends to do that with items that are hard to keep in stock. I found out the hard way when I RMA'd my 5870. :( I was really pissed when they just gave me cash back instead of a new cards cos 5870s were impossible to find at that time. I complained and they offered me a $25 rebate which I then used on my shiny new 5970 when it finally released. =)
 
risqu3 said:
no.

Just like with different memory capacities..different clock speeds will result in the lowest common factor being used.

Eg: 700/1200 with 900/1200 the 900/1200 will downclock to 700/1200. Unless you manually overclock the 700 to 900.
Click to expand...

It actually doesn't do this. It will run each card at it's default clocks unless you manually change them.

I've found having them all at the same clocks or as close as possible has worked out the best for me. I'm running all of mine at 900/1150.
 
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