270x Xfire or 290+270x Xfire

[goneferal]

Really looking to boost my GPU performance. I've been looking at some benchmarks and prices. I have a R9 270x 2gb currently.

I'm looking getting a Sapphire 270x with 4gb. for another $200

or

Radeon R9 290 4GB for $260
I would have the R9 crossfire with the 270x

Would it be beneficial to stick and crossfire with the same generation of cards, or go oddball it. Keep in mind the new 270x would have 4gb of vram.


Lastly would heat be an issue? I have an well ventilated case for the most part.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814202049&cm_re=270x-_-14-202-049-_-Product
http://www.newegg.com/Product/Product.aspx?Item=N82E16814202143&cm_re=290-_-14-202-143-_-Product

 

[i7Baby]

See http://support.amd.com/en-us/kb-articles/Pages/Crossfire-Chart.aspx

You can only crossfire the same cards.

 

[Rookie_MIB]

Exactly what ^^ he said. You can only crossfire the same class of cards - at least perhaps until the new rendering algorithm AMD is working on comes out. So, while you can crossfire different makers of different cards (ie: XFX 270x and an Asus 270x), crossfiring different classes of cards regardless of maker (ie: XFX 280x and XFX 290x) will not work.

 

[goneferal]

See http://support.amd.com/en-us/kb-articles/Pages/Crossfire-Chart.aspx

You can only crossfire the same cards.

I'm really tired, maybe a lil dumb lol. That chart indicates that they are not compatible because one requires a bridge and the other does not?

I thought i remembered reading that crossfire was different from SLI because you could link different generations of cards. Guess i heard wrong ¯\_(ツ)_/¯

Thanks for the help guys. Looks like i'm going 270x X2 with 6gb total

 

[grb121264]

you can in fact xfire two different cards you need the lower card in first pci e x16 the higher card wil take the properties of the lower card

 

[Rookie_MIB]

you can in fact xfire two different cards you need the lower card in first pci e x16 the higher card wil take the properties of the lower card

No. Crossfire does NOT work that way. They need to be in the same class - ie: using the same GPU. Here is the official chart from AMD:

http://support.amd.com/en-us/kb-articles/Pages/Crossfire-Chart.aspx

While you can have slightly different cards with regards to clock speeds in some respects - and the clock speeds will auto adjust to the lower of the two, the problem with crossfiring two vastly different cards in regards to frame rendering is that the frames are -alternated- between the two cards to be rendered. If one card is capable of rendering at 80fps and the other is only capable of 20 fps, you're going to get some jagging every other frame because one is rendering every .0125 seconds while the other renders at .05 seconds. That would create a lot of stuttering.

The point is to in general be able to render every frame at roughly the same rate - and you can't do that when you have two potentially vastly different GPU capabilities. As mentioned, DX12 may solve some of that by providing an asynchronous rendering mode utilizing different GPUs (including dGPU/iGPU combos) but no games have been released which can use it.

Besides, from a symmetry point of view, twin identical GPUs look better.