3D performance
Half-Life 2: Episode One
Valve introduced a number of visual enhancements for its second game using the Source Engine, including the high dynamic range (HDR) lighting demonstrated in their 'Lost Coast' playable technology showcase. Episode One is therefore more graphically demanding than the original HL2; just the ticket for our testing.
At 1920x1200 the X1950 XTX just 4% faster than the X1900 XTX, but some 17% speedier than NVIDIA's GeForce 7900 GTX. At 2560x1600, the gap widens to 7% between the X1950 and X1900, while our intrepid newcomer out performs the 7900 GTX by 31%.
With an X1950 CrossFire configuration, we can see a 1.5-1.6x improvement in framerates.
Straight off we see poor performance from the 7950 GX2. It should be able to comfortably beat the single-GPU cards, though probably not the X1950 XTX in CrossFire. However, we see it's only capable of beating X1950 and X1900 by a fractional margin.
The Elder Scrolls IV: Oblivion
Somewhat more taxing than HL2: Ep 1, as far as average framerates are concerned, is Oblivion.
ATI's cards prove to be comfortably faster than the GeForce 7900 GTX, in the region of 50% quicker, in fact. There still isn't much of a difference between the X1900 and X1950, however, X1950 6% quicker at both tested resolutions.
CrossFire shows some impressive performance increases at 1.75-1.8x. At 2560x1600 the greatest benefit can be seen, bringing the framerate up into the realm of the playable.
At 2560x1600, the 7950 GX2 seems appropriately fast, compared to the 7900 GTX. However, it only effectively levels with the single-GPU X1950 XTX and gets trounced by it in CrossFire. At 1920x1200 the situation is worse still for the GX2, it losing out to all of our ATI configurations.
Quake 4
Our final benchmark, for now, is the Doom 3 engine based Quake 4.
In this benchmark it's a much closer race, NVIDIA's GeForce 7900 GTX still coming last, but by a much smaller margin.
X1950 CrossFire doesn't yield anything near the improvements seen in our other tests, not even making it to a 30% boost over a single card. If Quake 4 is your game, then, CrossFire doesn't provide enough of a framerate benefit to make it worthwhile.
The GX2 finds its feet with Quake 4, rivalling the X1950 XTX CrossFire's performance in our first test run, but upping the resolution sees its performance drop back to almost that of a 7900 GTX. Something ain't right here, captain.
GeForce 7950 GX2 - Re-test
Concerned with the results from our 7950 GX2, we set about re-testing with a similarly specified system, but using an nForce 4 SLI Intel Edition mainboard, namely the ASUS P5N32 SLI SE Deluxe. Other aspects of the system remained the same. At the time of writing, we've only been in a position to re-test with Quake 4, which means some of the more dire results from HL2: Ep 1 and Oblivion can't be compared against i975X.
So, Quake 4 re-tests... At 1920x1200, on the P5N32 we got an average of 126.5 FPS, slightly slower than on the i975X Bad Axe board, but still close. At 2560x1600 we obtained a better result of 69.3 FPS, putting it ahead of the single-GPU solutions, but still behind our i975X tested X1950 XTX in CrossFire.
The changing figures suggest issues running the 7950 GX2 on i975X boards. Thoughts on that shortly.
