Does crossfire really work

[bushrat2]

Is SLI and Crossfire a gimmick or do they give twice the graphics power of a single card? Are two R6950 1GB cards in crossfire better then a single R6950 2GB card?

 

[Mousemonkey]

I don't see the numbers being 75% to 80%, more like 30% to 50%:

http://www.anandtech.com/bench/Product/331?vs=299

How do you work out percentages then? Some of those graphs show near on double the framerate.

 

[Gothams Finest]

There are a few poorly coded or new and still buggy games out there that will perform bad no matter how much GPU power you throw at them, people just need to remember that and not think it is a problem with their hardware. Skyrim is definitely shoddy at the moment.

I couldn't agree more.

 

[Gothams Finest]

How do you work out percentages then? Some of those graphs show near on double the framerate.

I was wondering that too.

 

[Mousemonkey]

I was wondering that too.

Hmm, kids these days huh?

 

[tjcoops]

Pretty sure AbdullahG is just calculating the difference between the frame rates 😛

 

[AbdullahG]

My bad. I was referring to single card performance being 30 to 50% slower than dual card performance. That' what I was pointing at, though I may have stated it wrong. I was using dual card performance as a base, rather than single card.

Ex:
2x HD 6950 = 60FPS
1x HD 6950 = 30FPS <---50% slower than dual-card setup

 

[jijoslin]

I've had cf5850's as well as my current crossfire hd6950 2gb sapphire dirt 3 edition cards, and I run triple eyefinity at 5760 by 1080 and crossfire helps alot on most games, way more than 30 percent

 

[badtaylorx]

wow......there is a whole lot of mis/untrue/incorrect information in this thread....may i suggest a mod bury it before someone mistakenly passes up on a second gfx card

 

[Energy96]

The only misinformation was by Bushrat (the OP) and Abdullah.

 

[AbdullahG]

The only misinformation was by Bushrat (the OP) and Abdullah.

Though I corrected myself...

 

[Energy96]

Though I corrected myself...

Yes you did, but originally it was misinformation. I wasn't poking at you, I was just pointing out there was very little misinformation here and all of it was corrected.

 

[AbdullahG]

Yes you did, but originally it was misinformation. I wasn't poking at you, I was just pointing out there was very little misinformation here and all of it was corrected.

It's fine. I didn't take it personally, as it was never intended to be an insult.

@OP
To answer your question:
Yes, CrossFire works. It-on average-doubles the performance vs a single card setup with the same card. Two HD 6950 1GB will outperform a single HD 6950 (whether it be 1GB of 2GB). However, no all games support CrossFire or work well with it.

EDIT: 60% to 80% performance boost

 

[4745454b]

I don't like that "doubling" word. Very few games show perfect scaling. As I've mentioned before, you'll probably see anywhere from 60-80% increase in most titles.

 

[Gothams Finest]

I agree, 60% to 80% is about right.

 

[SpamShadow]

I'll put in my two cents. I've spent the past few months getting my 2x6870s into working order. Sometimes (in the case of Metro2033) it was a simple plug and play. Installed cards, got 60 frames. It was incredible.

And then there's Skyrim, BF3, Cryostasis, Crysis 1 and 2, and a multitude of other games that took me a good while (several weeks) to get working. It's like with every game release comes a few days of tinkering to get your system working with it. So far I haven't met a game I couldn't play, but some were definitely compromises.

I would tell you to go Nvidia, but they have their share of problems, too. No crossfire setup is perfect, and it would be a bummer to drop $500 on an Nvidia SLI setup and have to fiddle with it to get it to work, too.

I say its worth all the effort if you actually play games that need it. I never thought I'd see playable framerates in Metro2033 or Cryostasis, but I do now. Also, keep in mind, Crossfire shines best at high resolution, so if you aren't playing in 1080 its not quite as worth it. The fact of the matter is if you want to play it like its meant to be played, dual gpu setups will certainly get you closer to that goal (for the most part).

 

[AbdullahG]

Okay, 60% to 80% on average is the final performance boost estimate.

 

[Energy96]

And then there's Skyrim, BF3, Cryostasis, Crysis 1 and 2, and a multitude of other games that took me a good while (several weeks) to get working. It's like with every game release comes a few days of tinkering to get your system working with it. So far I haven't met a game I couldn't play, but some were definitely compromises.

I would tell you to go Nvidia, but they have their share of problems, too. No crossfire setup is perfect, and it would be a bummer to drop $500 on an Nvidia SLI setup and have to fiddle with it to get it to work, too.

I can't even fathom why that would be necessary, Crossfire is absolutely abysmal if you are having to do that. Fiddling for weeks?? with what?? I have never had even a single issue with my SLI 580's on any of the games I have played. I have never done anything beyond simply install the newest driver when it is released about every month.

I know skyrim has had a few issues for people, not just with SLI, but that game's coding is complete trash in spite of its really nice looking graphics.

 

[Energy96]

I don't like that "doubling" word. Very few games show perfect scaling. As I've mentioned before, you'll probably see anywhere from 60-80% increase in most titles.

I think it really depends a lot on your resolution. If you are already getting frames in the 80 plus department at typical 1080 resolutions with a single GPU SLI isnt going to boost you as much as when you are running at 1440 or even 1600 resolution. I know in most really demanding games for me at 2560x1440 with max settings when I turn off SLI for giggles My frames drop by roughly half on average. (60-80 fps to 30-40 fps for example) Granted, many of those games also run well over 100fps in many points in the game. Frames can vary a lot in a game depending on what is going on, but my min frame-rate is definitely roughly double.

SLI really shines when playing at higher resolutions in my experience.

 

[SpamShadow]

I can't even fathom why that would be necessary, Crossfire is absolutely abysmal if you are having to do that. Fiddling for weeks?? with what?? I have never had even a single issue with my SLI 580's on any of the games I have played.

You'd be surprised how many hours you can spend changing out RadeonPro profiles and settings, trying different drivers, researching on the web. A lot of times it comes down to simple driver/game updates. I do hear a lot more people saying that don't have problems with SLI than Crossfire.

Sometimes it was just a single setting, something to do with AA or somesuch nonsense. Changing it would make the difference between the game running and not running. I tend to attract issues when it comes to computers...

 

[weedunc]

Generally speaking I believe you should always go for the most expensive card you can afford and run it on it's own. Crossfire is too much of a loose cannon at the moment in terms of compatability and drivers to consider for new-builds.

My stance on crossfire is that it gives you the opportunity later on to buy a duplicate card a year or so down the line when it's much cheaper - upgrading your rig. Rather than buying an entirely new 'hot' card all over again.

 

[WGW]

As of today, 12/28/15 using two AMD R9 270x's in crossfire it only yields between 0%-30%. I'm very disappointed. Some games take adva