This member on ocUK swapped his GTX 680 SLI setup for AMD 7950 xFire.
He then compared the performance difference @ 5760 x 1080, the results are surprising.
http://forums.overclockers.co.uk/showthread.php?t=18455827
What he had to say about it
He then compared the performance difference @ 5760 x 1080, the results are surprising.
http://forums.overclockers.co.uk/showthread.php?t=18455827
What he had to say about it
OK so the results are in and if you discount Borderlands 2 which is obviously going to be a lot slower due to the lack of PhysX processing on the GPU, it is practically a clean sweep for the 7950 over the 680. Hierarchically these cards shouldn't even be comparable - the GTX 680 is nVidia's top end part whereas the 7950 is AMD's second top end part behind the 7970.
There are couple of caveats which have to be stated first which actually would have increased the results in AMD's favour even more.
I had a dodgy 7950. One of them (which I had to move to the bottom slot to stop it spontaneously combusting) had a dodgy heatsink connection which resulted in thermal throttling would you believe it if it was in the top slot. This severley limited my overclocking capability and I had to bench at 1150/1700. Not a MHz more was available from the second card and to be honest this was pushing the limits already. I was happy to push the limits if I was touching 1250 but it just felt like a gigantic anti-climax to be pushing the card so hard at only 1150 MHz. A reasonably clocked 7970 can expect to easily add 10% onto myself and a 7950 matching my first can add on 5%.
Discussing BF3 first as it seems to be everybody's favourite benchmark: comparing average FPS reveals a 26% advantage for 7950 crossfire over 680 SLI at this resolution. To give this result some context: at 1920*1080 at the same clock speeds (1150/1700) the 7950 was 8% slower so that is a 34% swing in favour of the 7950 moving from 1920*1080 to 5760*1080. This is down to the 384 bit bus which really allows the card to stretch its legs at 5760*1080.
On the subject of microstutter and or any other visual discomforts: there was nothing major. If I was forced to pick something I would say the AMD set up was just a little bit less smooth feeling than 680 SLI but without any way to measure this it's difficult to really pin point or analyse so you can make of that subjective observation as you will. I would like to think it is the effort nVidia have made to eliminate it that produced that slightly more polished feel across 3 screens.
nVidia's pricing is an absolute mess. The fact that you could potentially (as I have) move from a 680 SLI set up to a 7950 CF set up and make money on the sell up and get better performance would be amusing if it wasn't true. nVidia just can't compete on paper at this resolution with this generation of cards and there is no question of what is a faster set up. I'm obviously not going to recommend everyone sell their 680's and move to 7950's (more of which in a second) just because of this but it is worth stating nonetheless that with the free games and the price of 7950's it really is a completely viable option.
I'm not going to talk about the numbers themselves because they do speak for themselves. You can take each result at face value and I have nothing else to add on top of what the numbers say. However there is a major, major problem which would seriously make me think twice about staying with AMD CF for triple screen and that is WORK AROUNDS. (sorry for the anti climax here!)
Now I'm going to list a load of things which are frankly a combination of sloppy, not as nice as nVidia or borderline broken. Some can be worked around (that phrase is going to crop up a lot) but that's not really the point and if you reply to me saying "yes, but you can do this..." then you're missing the point.
I would say that overall I preferred Surround to Eyefinity. Eyefinity does the bits that Surround doesn't - like switching from triple screen to extended desktop quickly and it saves your profile but it also doesn't do some things out the box that Surround does.
- GPU usage flies about from 10-50% while idle in Eyefinity
- Overclocking requires unofficial patches, unlocking, reboots - it doesn't sometimes work on both cards
- Because all 3 monitors have to plug into one card - idle temperatures are high
- No way to manually enter the number of pixels you want when bezel correcting
- Connections on the cards leave a lot to be desired
- The cards do run quite hot and need to have a fairly aggressive profile to keep them cool while overclocked which will ruin your eardrums with two custom cooled cards
- Card 2 monitoring doesn't work properly unless you disable ULPS which means more idle noise
- Occasional blue screens (though this could be down to needing to re-format)
The fact you can't idle properly in silence because the card has to clock up to drive all 3 monitors is major pain. I'm as insensitive to noise as the next guy who overclocks the hind parts off his machine but this was too much. I'm actually looking forward to getting the broken card out the machine and unplugging the two monitors... it was that bad overall but you have to understand my opinion here is skewed by dealing with a blatantly broken card.
Now I haven't researched enough or tried enough things to say whether these are permanent issues or things that can be "worked around" but my point is more that you shouldn't have to work around these things and they should work better out of the box. The only problem I had with Surround was switching to single GPU/single monitor which caused a hard reboot.
nVidia have triple screen almost completely nailed as they have two dual link DVI slots and a DisplayPort slot which makes it so easy to connect three screens to. For SLI users you plug 2 into DL DVI on card 1 and 1 into DL DVI on card 2. Cards can successfully clock down to idle speeds as a result. Obviously the fact they have such a robust process in place for it does make the card a little bit paradoxical with a 256 bit bus but that's already been debated above.
If you already have a custom loop then the lure of 7950 becomes even greater. These could really fly with adequate cooling.
To summarise - on paper these cards are a fantastic option. I would probably get a custom cooled one like the Twin Frozr and pair it with one of the blow out the back types like the HIS IceQ. This would be a good combination to go for. That said you need to be prepared to do some leg work to get round the little qwirks which just don't exist on the equivalent nVidia side. Crossfire on its own was fine, it was crossfire paired with triple screen which caused the little niggles.
If you can get past these minor issues (and they are minor in truth) or they don't bother you in the first place then this is what you should look at.
What is there to say about performance costing £500 which is quite simply, much, much, much faster at this resolution than two of nVidia's top end cards which costs over £300 more?
