Stupid crossfire question

[Praytus]

Been a while since I looked into the technology, but do both cards in a crossfire config need to be from the same manufacturer and part number?

 

[adairusmc]

Originally posted by: Praytus
Been a while since I looked into the technology, but do both cards in a crossfire config need to be from the same manufacturer and part number?

No, they do not.

For example, I have a visiontek 4870X2 crossfired with a Sapphire 4870 1Gb.

I am not totally sure what cards with xfire with each other, but if they are the same card from different manufacturers it should work fine.

 

[AmberClad]

No.

In theory, you can even Frankenfire a 4850 and a 4870, for example. (In practice, it's not really a great idea.)

 

[nRollo]

Originally posted by: AmberClad
No.

In theory, you can even Frankenfire a 4850 and a 4870, for example. (In practice, it's not really a great idea.)

The "flexibility" of CF has never really been the advantage it was originally made out to be as the slower card(s) slow down the more powerful ones due to load balancing constraints.

 

[Praytus]

much thanks

 

[apoppin]

Originally posted by: nRollo

Originally posted by: AmberClad
No.

In theory, you can even Frankenfire a 4850 and a 4870, for example. (In practice, it's not really a great idea.)

The "flexibility" of CF has never really been the advantage it was originally made out to be as the slower card(s) slow down the more powerful ones due to load balancing constraints.

sure it is

when my 2900xt got too slow for DX10 games, i added a cheap $100 2900Pro that i overclocked to 2900xt speeds
- a damn cheap "upgrade" that brought my 2900xt/frankenfire up to GTX ultra speeds

it is a feature that evidently Nvidia cannot implement due to technical considerations

did you focus guys ever find out if GTX280 and GTX285 can SLi together ?
- i would prefer to do that instead of buying two 285s

 

[dakels]

Originally posted by: nRollo

Originally posted by: AmberClad
No.

In theory, you can even Frankenfire a 4850 and a 4870, for example. (In practice, it's not really a great idea.)

The "flexibility" of CF has never really been the advantage it was originally made out to be as the slower card(s) slow down the more powerful ones due to load balancing constraints.

4870+4850 is not better then 4870 alone? Granted I doubt its even close to optimal but it's worse then 1 4870? Is the difference so marginal its not worth it? I assume it's also conditional on the application.

 

[krnmastersgt]

Originally posted by: dakels

Originally posted by: nRollo

Originally posted by: AmberClad
No.

In theory, you can even Frankenfire a 4850 and a 4870, for example. (In practice, it's not really a great idea.)

The "flexibility" of CF has never really been the advantage it was originally made out to be as the slower card(s) slow down the more powerful ones due to load balancing constraints.

4870+4850 is not better then 4870 alone? Granted I doubt its even close to optimal but it's worse then 1 4870? Is the difference so marginal its not worth it? I assume it's also conditional on the application.

I think what Rollo meant is that a 4870+4850 = 2 4850s, so the benefit of Crossfiring between 2 different models isn't as appealing.

 

[dakels]

Interesting, so how does an application treat a mixed crossfire setup if it doesn't support crossfire? It reads the first AGP slot and that's it? So say i had a 4870 in the first slot and a 4850 in the 2nd. A game that doesn't support CF would run off the performance of the 4870?

 

[imported_Asianman]

I think it may use the one that your monitor is plugged into. But I'm not too sure, still, anything that doesn't support crossfire is likely to not need more than a HD 4850

 

[chizow]

Originally posted by: apoppin
it is a feature that evidently Nvidia cannot implement due to technical considerations

did you focus guys ever find out if GTX280 and GTX285 can SLi together ?
- i would prefer to do that instead of buying two 285s

Its not a technical limitation, Nvidia allowed mixed and matched SLI with different spec'd parts as far back as G80 GTS with the 96 and 112SP variants. You could even SLI 320MB and 640MB GTS. I've also read similar from an EVGA tech saying you could SLI 192 and 216SP GTX 260s, although you'd only get 192SP SLI. If anything its probably a driver limitation preventing this with vendor ID strings. Lowering performance to the lower of the two is also probably a consideration for preventing such pairings.

As for 280 and 285 SLI, even if you could, why would you? You'd get 280 SLI performance, and in that case you could save by just buying a 280. Unless you want to bench the 285 separately, paying more for less in SLI doesn't make any sense.

 

[apoppin]

Originally posted by: chizow

Originally posted by: apoppin
it is a feature that evidently Nvidia cannot implement due to technical considerations

did you focus guys ever find out if GTX280 and GTX285 can SLi together ?
- i would prefer to do that instead of buying two 285s

Its not a technical limitation, Nvidia allowed mixed and matched SLI with different spec'd parts as far back as G80 GTS with the 96 and 112SP variants. You could even SLI 320MB and 640MB GTS. I've also read similar from an EVGA tech saying you could SLI 192 and 216SP GTX 260s, although you'd only get 192SP SLI. If anything its probably a driver limitation preventing this with vendor ID strings. Lowering performance to the lower of the two is also probably a consideration for preventing such pairings.

As for 280 and 285 SLI, even if you could, why would you? You'd get 280 SLI performance, and in that case you could save by just buying a 280. Unless you want to bench the 285 separately, paying more for less in SLI doesn't make any sense.

why ? .. i want to test and compare my gtx280 to 285 .. and naturally i would overclock my 280 to approach the 285 clocks .. i would only be "losing" a tiny bit of performance over true SLi'd 285s

it is about time i examine SLi .. i have much experience with Crossfire and CrossfireX and i want to test out the Nvidia side of multi-GPU

it appears to me that micro stutter is less now than previously with AMD's X2 and X3