Single 6990m vs Crossfire 5870m

So if I am understanding it correctly, the single 6990m is more powerful then the 5870m's in crossfire, but how much better is my question? I mean what kind of performance gain are we talking:

No gain 0-5%

Marginal gain of 5-10%

Significant gain of 10-15%

or

Substantial gain of 15% or more

Anyone who has done this particular upgrade? I am sure lots of people are doing 6970s or 6990s in crossfire...but damm if that isnt alot of money. I'd almost rather buy a whole new laptop. But I might consider the upgrade if we are talking "substantial gain" in performance for the single GPU config.

 

ATI Mobility Radeon HD 5870 Crossfire - Notebookcheck.net Tech

AMD Radeon HD 6990M - Notebookcheck.net Tech


Looking at just fps on games and benchmarks, the 6990 seems as powerful as a crossfire 5870 setup.

However, crossfire the 6990's and you get around a 75% boost in fps compared to dual 5870's.

I personally prefer single card systems, due to the fact I won't have to worry about xfire not being supported on newer games without waiting a few days for a new driver, but i'd wait for more input from 5870/6900's owners.

 

look at this

Spoiler

BTW what screen res you mean.
If WXGA+ and CF it'll be much faster than 6990m + FHD

 

That chart wouldn't be a completely accurate way to look at things. Differant motherboard, differant CPU's all that stuff comes into play. To have an accurate idea on how components fare against each other, they should be run on identical systems. Best case senario would be the same system, just swapped out GPUs.

At OP, somone in the 6970 Guide thread may have stock benches of thier 5870 vs 6970/6990 setup. I may back home, but I don't know if I have stock runs though.

 

Was playing Crysis last night and had my X-Fire turned off without knowing was getting 30+ FPS with highest settings. So I'd say about 5% or so. Stock clocks.

 

An overclocked 6990M is as powerful as 5870M CF. I have had them both in the same exact computer, same exact configuration. So no, you won't see a 'substantial' gain in performance. Look at the numbers though.

Mythlogic sells the 6990M for $546 plus shipping. I sold my 5870s for $400.

No more CrossFire headaches, but, you can upgrade later on if you choose to.

Less power consumption. Less overall heat production. More shaders. Tessellation monster. Newer architecture. Smaller die. There is no reason in the world not to get a single 6990M. Once you sell your 5870s, you won't pay much for the card at all. You don't have to foot the bill for a whole new M18x, and you get to keep the RGB screen.

 

And with a single card you have none of those Crossfire issues...you will always get a solid number across games whereas CF it depends on how good the support is.

 

One of the reasons I love Crossfire 6990s. Can run a single one no prob, and if Crossfire support is good, run crossfire

 

Could you please write about temps (6990m) in R2?

 

Stock for stock, the cf 5870 is about 1-5% more powerful than a single 6990 according to notebookcheck...depends on what you are doing. This can be easily corrected with a small overclock on the 6990.

However the advantage of the 6990 is that its a single card. You don't have to deal with dual card support and drivers etc...