The first diagram helps compare the two Sapphire cards at their rated frequencies. Here is how slower the Sapphire Radeon HD 6850 Vapor-X is compared to the Sapphire Radeon HD 6870 DiRT 3 Edition:
As you can see, the senior card enjoys a rather large advantage, up to 33% in one game. The average advantage across all the tests is 17.6% in the MSAA-less mode and 16.3% with MSAA. On the other hand, the Radeon HD 6870 DiRT 3 Edition is about 24% more expensive, so the Radeon HD 6850 Vapor-X may look a better buy, especially as the latter card gets closer to its cousin when overclocked.
So, the Radeon HD 6850 clocked at 960/4800 MHz is almost as fast as the Radeon HD 6850 clocked at 920/4200 MHz. The average gap across all the tests is no larger than 1%. Of course, the Radeon HD 6870 can be overclocked as well. Will it be able to compete with the more expensive MSI Radeon HD 6950 if the latter works at its default frequencies? Let's see.
Well, the overclocked Sapphire Radeon HD 6870 DiRT 3 Edition doesn’t show us anything exceptional. It is 8.7% and 10.1% behind the MSI Radeon HD 6950 with MSAA off and on, respectively. The gap narrows in Tom Clancy’s H.A.W.X. 2 and Crysis 2 and gets larger in S.T.A.L.K.E.R.: Call of Pripyat, Aliens vs. Predator (2010), Left 4 Dead 2 and the synthetic benchmarks.
Now let’s compare the Sapphire Radeon HD 6870 DiRT 3 Edition with the Gigabyte GeForce GTX 560 Ultra Durable at their default clock rates, the latter card serving as a baseline.
So, the Sapphire card is ahead in Just Cause 2, Sid Meier’s Civilization V, World of Planes and Aliens vs. Predator (2010) whereas the Gigabyte is superior in 3DMark Vantage, Lost Planet 2, Tom Clancy’s H.A.W.X. 2, DiRT 3 and Hard Reset. They are roughly equal in the rest of our games and tests. The Gigabyte GeForce GTX 560 Ultra Durable is about $20 cheaper than the Sapphire Radeon HD 6870 DiRT 3 Edition and $20 more expensive than the Sapphire Radeon HD 6850 Vapor-X, the latter being slower in almost every test.
We can only add that you can request any summary diagram based on this test session in the comments. Here is a table with the full test results.
Sapphire’s Radeon HD 6870 1GB Dirt 3 Edition and Radeon HD 6850 1GB Vapor-X cards are truly unique products with one-of-a-kind coolers, increased frequencies, a full selection of interfaces, nice-looking and reliable packaging and very large accessories bundles. Moreover, the Vapor-X also boasts an enhanced power system which should make it more stable at high frequencies and make its life span significantly longer.
On the other hand, we haven’t found anything very out-of-the-ordinary about these products. The coolers are efficient but not as quiet as we might wish they were. Their overclocking potential is high but not record-breaking. Their performance is up to the mark for their class, but they’ve got a strong opponent, GeForce GTX 560. So, the new cards from Sapphire are surely interesting products but can hardly be called a perfect buy in their respective price groups.
Well, perhaps there is no such thing as a “perfect buy” anyway and you always have to compromise. The choice is up to you.