2 7970's Crossfire

tom_taylor97 · Jul 10, 2013

I am considering getting a second 7970 and using crossfire but i am unsure as whether to because i have heard that is causes problems. What problems does it cause because i will only have the £300 it will cost to buy the second 7970 so if i sell my current 7970 i will not be able to buy either the GTX 690 or the GTX Titan which will be the only cards that will be worth upgrading to. I have looked at benchmarks that say 2 7970's outperform the GTX 690 & Titan by a minimal amount but cost about £150-£200 less to buy. What should i do?

bystander · Jul 10, 2013

Wait a month, see if AMD gets out the crossfire frame metering fix at the end of the month like they said they would.

tom_taylor97 · Jul 10, 2013

bystander :

ok thanks

Pinhedd · Jul 10, 2013

I have two 7970s. There are certainly problems with some games but most of the time they work fine.

tom_taylor97 · Jul 10, 2013

Pinhedd :

Could you list a few games that you encounter problems with please, do games like arma/dayz and battlefield have problems?

17seconds · Jul 10, 2013

Here's the problem graphically illustrated. Traditionally measured FPS is referred to as "Hardware FPS", the red bars in the chart below. With poor frame metering, frames tend to jumble up and sit on top of each other, and be only partially displayed on screen. FPS monitors then end up counting all of these frames as whole frames, even though only small parts and slivers are actually being rendered. This essentially cheats the FPS monitor into reporting higher FPS numbers than what is actually being displayed on screen. When you filter out all the junk, called "runt" frames, you end up with the "Practical FPS" number shown in black below. (Yes, it only affects Crossfire.)

Clearly, adding a second 7970 does not do much more than just a single card would in this example, and may even be worse by introducing microstuttering and game compatibility issues. A pending driver fix has been reported due out at the end of this month. So there is hope if you decided to proceed with your plan to add another card in Crossfire. Without the driver fix, it would be a waste of money.

http://www.tomshardware.com/reviews/geforce-gtx-770-gk104-review,3519-12.html

Intel God · Jul 10, 2013

17seconds :

Here's the problem graphically illustrated. Traditionally measured FPS is referred to as "Hardware FPS", the red bars in the chart below. With poor frame metering, frames tend to jumble up and sit on top of each other, and be only partially displayed on screen. FPS monitors then end up counting all of these frames as whole frames, even though only small parts and slivers are actually being rendered. This essentially cheats the FPS monitor into reporting higher FPS numbers than what is actually being displayed on screen. When you filter out all the junk, called "runt" frames, you end up with the "Practical FPS" number shown in black below. (Yes, it only affects Crossfire.)

Clearly, adding a second 7970 does not do much more than just a single card would in this example, and may even be worse by introducing microstuttering and game compatibility issues. A pending driver fix has been reported due out at the end of this month. So there is hope if you decided to proceed with your plan to add another card in Crossfire. Without the driver fix, it would be a waste of money.

http://www.tomshardware.com/reviews/geforce-gtx-770-gk104-review,3519-12.html

I hope amd fixes this problem because i'd like to buy a 9 series card or two

Pinhedd · Jul 10, 2013

tom_taylor97 :

Battlefield 3 - No problems. Crossfire works beautifully. The image posted above by 17seconds was produced using a beta driver which had massive crossfire problems across the board. Shame on Tom's for that.

Arma II - CPU bound game. I do not believe that either Crossfire or SLI are supported, but I haven't played it in ages

Skyrim - Crossfire not necessary at all, but occasionally turns on/off when zoning which causes some strange framing issues.

Max Payne 3 - Crossfire works great during gameplay, but static images during cutscenes flicker. I haven't tested this without Crossfire though

Crysis - No problems, works great

Crysis 2 - Works great but requires a small in-game workaround to get it to stick

Far Cry 3 - Works great, but normal rendering issues with FC3 persist

Metro 2033 - No issues

Borderlands 2 - No issues, not even necessary

The Witcher 2 - No issues with crossfire specifically, but there are some other rendering problems that remain unresolved.

bystander · Jul 10, 2013

I have a feeling that you either play with v-sync on at all times, use a FPS limiter or you just don't notice microstutter, because every driver version they've tested with FCAT review show huge problems in a few of those games you claim work great.

Pinhedd · Jul 10, 2013

bystander :

I play at 2560x1600 on a 30 inch monitor with VSync on most of the time. I am aware that there are some frame timing issues, but I certainly don't notice them in any case that I mentioned as working great.

bystander · Jul 10, 2013

Pinhedd :

The crossfire problems are mostly fixed with FPS limiting. Vsync limits FPS, so that is not surprising. The problem is v-sync isn't always optimal, as it can introduce stuttering if below your refresh rate, or a drop to 30 FPS, and it introduces latency.

Pinhedd · Jul 10, 2013

bystander :

Pinhedd :

The crossfire problems are mostly fixed with FPS limiting. Vsync limits FPS, so that is not surprising. The problem is v-sync isn't always optimal, as it can introduce stuttering if below your refresh rate, or a drop to 30 FPS, and it introduces latency.

VSync is not a problem with 7970s. The framerate is often well over 60. Turning VSync on improves image quality and keeps them from dumping too much heat into the environment.

iam2thecrowe · Jul 11, 2013

Pinhedd :

if your running triple monitors then your still going to drop below 60fps though, which is the only real reason to have more than 1 7970 imo. Frame limiters are a fix, but your hindering the cards performance by using them, so you may as well just use 1 card and save the money. I had 6850's crossfired and i couldnt believe the difference of my single gtx660, 100% smoother playing experience, even though on paper they have roughly the same performance. My advice, stay away from crossfire until amd get their sh!t together.

tom_taylor97 · Jul 11, 2013

bystander :

I also play with v-sync so the micro stutter shouldn't be a problem but i will wait until the end of the month and see if the new driver is introduced to fix the problem. Thanks for the help.

tom_taylor97 · Jul 11, 2013

iam2thecrowe :

Pinhedd :

if your running triple monitors then your still going to drop below 60fps though, which is the only real reason to have more than 1 7970 imo. Frame limiters are a fix, but your hindering the cards performance by using them, so you may as well just use 1 card and save the money. I had 6850's crossfired and i couldnt believe the difference of my single gtx660, 100% smoother playing experience, even though on paper they have roughly the same performance. My advice, stay away from crossfire until amd get their sh!t together.

The main reason i am considering crossfire is because the only single cards it is worth me upgrading to is the gtx690 or the gtx titan which will cost £150-£200 which i will not be able to afford and that is if i was able to sell my 7970 for the price i bought it for. I know crossfire can cause problems so i am going to wait fir the new driver and ask people opinions again but i think it is the best option at the moment to get any sort of a performance increase.

sancco · Jul 11, 2013

I'm in the same situation. I've got a 7970 and need more power. I'm steering well clear of Crossfire though, it looks like one big headache.

I'm gonna switch to NVIDIA and the GTX780, and then SLI later on. Only reason I went for 7970 over 680 was the 384-bit bus width, which NVIDIA has caught up with in this current generation.

tom_taylor97 · Jul 11, 2013

sancco :

why would you consider sli but not crossfire? aren't they both the same thing but from different companies or is sli better and doesn't cause problems?

smeezekitty · Jul 11, 2013

SLI has less problems overall.

Intel God · Jul 11, 2013

tom_taylor97 :

Nvidia's driver team is simply better in every aspect then Amd's. I mean its not even close.

sancco · Jul 11, 2013

smeezekitty :

Turns out you can draw differences between the two companies without being a fanboy. Crossfire is nowhere near as good as SLI. http://www.tomshardware.com/reviews/geforce-gtx-780-performance-review,3516-29.html Second last paragraph. Also check the benchmarks. There are some instances (BF3) where Crossfire yields a 0% gain over a single gpu, whereas SLI offers 75%+ And this doesn't even touch on bugs and crashes.

tom_taylor97 · Jul 11, 2013

Thanks for the help, i think i will most likely stick to using my tv instead of buying a monitor and save up for a gtx titan instead. The crossfire seems to be a waste of money and time due to problems. If they manage to fix these problems before i buy the titan i might reconsider but at the moment the titan will be my most likely choice.

smeezekitty · Jul 11, 2013

I never said that crossfire wasn't broken. I recommend NVidia to anybody wanting to run multi-GPU.

But his comment about NVidia drivers being so superior irked me. Remember who was it that made drivers that FRIED GPUs?

Intel God · Jul 11, 2013

What's below looks broken to me

2 7970's Crossfire

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