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7950 Crossfire vs 680 SLI at 5760*1080 (Eyefinity/Surround)

Rusty0611

Rusty0611

Rusty0611

Soldato
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With the new drivers for AMD enabling their cards to establish a healthy lead over their nVidia counterparts at the extreme 5760*1080 resolution, I have decide to swap over and actually quantify the difference in performance to give people an indication.

The reasons for swapping was not due to VRAM or any other kind of conspiracy theory. Now was a good a time as any to sell up on the 680's and swap to what I believe will be faster triple screen performance and with the selling on of the old cards and the games, I can actually make money and potentially achieve quite a large performance increase. This is quite frankly ludicrous and nVidia do need to look at their pricing structures if they want to compete above 1920*1080.

There's a real lack of data around on Surround/Eyefinity performance and if you discount obvious bias even less! It's difficult to jump into triple screen gaming without knowing how your hardware will perform so even if this helps one person before they buy I'll be happy.

Testing machine:

i7 3770K @ 4.5 GHz
8GB of Geil 2133 MHz RAM
Gigabyte Z77X-UD3H with the latest BIOS
680 SLI @ 1270 MHz core and ~ 7 GHz effective memory speed
7950 Crossfire - speeds TBC

The nVidia tests were run on 306.23 drivers and the AMD tests will be on the 12.11 beta's.

I will be benching at a high overclock to typify what I will term, your average 7970 overclock. So an overclock in 7970 terms that the majority of people will settle on as not pushing the limits of the card to the extreme with noise/heat and a comfortable balance of performance. So with that caveated you will be able to interpret my results as within a percentage point or two of what a 7970 crossfire set up can achieve on the latest drivers. It's worth stating for clarity that I understand that 7970's may go further but I still feel this is helpful as a comparison of the card above my 7950's as well as a 7950 comparison itself.

Complicated waffle over... Games to be benched:

BF3 Operation Swordbreaker
Borderlands 2
Metro 2033
Skyrim
Dirt Showdown
Sleeping Dogs
MOH Warfighter
Guild Wars 2

Unfortunately my first 680 is departing tonight so I can't run any more than what I have already benched. The 680 results are already compiled and available in the OCUK benchmark thread.

I will update this thread as I go on and then we can discuss etc.
 
BF3 - will compile into one graph when complete:

bf3multicomp.png


1f6pv.png

6nF1y.png
 
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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! :D)

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.

  • 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)

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.

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?
 
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Forgot about the time at work and then realised delivery is due between 15:55 and 16:55. Better get a move on!

Cheers guys. I'll probably bench before re-installing Windows but not completely decide yet.
 
spoffle said:
It's probably gonna be a good idea to sleep with one eye open now that you've got AMD drivers on your PC.
Click to expand...

:D

I have never had problems personally with them.

tommybhoy said:
Cool, any chance you can let me know if the second card spins down in desktop the way it should?

I'm sorely tempted to get a 50 if it does as I'm thinking of giving FC2 and Hitman a try, so it would give me a nice discount on the 50.

Unless you know someone selling them cheap. ;)
Click to expand...

Ha ha. My codes haven't come for the "Never Settle" thingymabob. Guess they'll follow in email in a few days.

Might do a few giveaways.

Just did a final bench for MoHWF on the mission seen in the trailer thing in the water and then up the coast.

Ran out of VRAM even with Windows Aero disabled. Before anyone says, "I told you so!", before the VRAM ran out I was only getting about 15 FPS anyway.

Game didn't crash it was just horrendously stuttery. This is the first time I have actually ran out of VRAM with 2GB at 5760*1080 although as I have said, it's a moot point because the frame rates weren't otherwise playable anyway.

The game runs like dog, while managing to look worse than BF3.
 
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Cards look sleek in my case :D. Much nicer aesthetically than previously. Stock clocks on 3D Mark 11 produced a score of like 14K graphics score without the CAPS installed.

Are there any 12.11 CAPs going anywhere or is the 12.10 only?
 
Really struggling to work out what is stable and what isn't - it's going to be some time before I complete some benches and I definitely need to re-install Windows. My 3DM11 score is about 1000 points down on someone with the same clocks!
 
dave_beast said:
Are you using Afterburner to overclock? If so, remember to add +20li board power and don't be afraid to up the vcore.
Click to expand...

Yeah. I've unlocked the clocks in there and everything. Just need some more time to work out what's stable etc. I'm just about there on card one although it is taking a long time. Then I need to work out card two's limits.
 
Off topic but I am impressed with how the performance is on 7950 number one with even a smallish overclock:

Operation Swordbreaker 1080p:

Mild OC of 1150/1500:

Frames, Time (ms), Min, Max, Avg
29451, 340191, 58, 139, 86.572

Surprisingly close to "the beast".

Frames, Time (ms), Min, Max, Avg
31648, 344622, 59, 164, 91.834
Click to expand...
 
dave_beast said:
You should be able to ramp up that memory clock a fair bit at stock volts, try 1600 mhz first
Click to expand...

Given up for the night. Will re-commence tomorrow. Though may just bench at 1150/1600 to get an idea. Though if I've got a pap clocker I do need to know ASAP to decide if to return.

The first one seems OK. Not golden but very good.
 
Anyone know how to unlock Afterburner for the second card when you have two? The unlocked limits are applying only to card 1.

Going to swap them over to check them individually but would be helpful to know regardless.
 
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