So, finely we come to the all important testing, which this time is a bit different to usual. Bearing in mind the previous page's caveats about how this card is likely to perform we have extended our game testing just this once to include five of our favourite games of the last year or so. It's not a comprehensive list and there's every chance you may find a game that doesn't play nice with the X2, but we reckon if it can get through our extended list of titles it shows the X2 is well on its way to being a viable solution.
New to the table are Bioshock (our Game Of The Year), The Elder Scrolls IV: Oblivion, World In Conflict, Call Of Duty 4, and Supreme Commander. Each game is run at three resolutions - 1,680 x 1,050, 1,920 x 1,200, and 2,560 x 1,600 - with anisotropic filtering set to 16x and multi-sampling transparency anti-aliasing turned on. Due to time constraints we've only tested at two full screen anti-aliasing settings - off and 4x - where applicable but we feel that should be enough to demonstrate things nicely.
We used a combination of in-game benchmarks and manual run-throughs, using FRAPs, to record results and each setting was repeated three times and the average taken, to ensure a fair and accurate final figure.
As can clearly be seen, the X2 and 8800 Ultra take turns in claiming top spot with the Ultra probably just coming in ahead overall. What's important to note, though, is how relatively small the increase in performance from the single 3870 to the X2 is for many of the games. Sure there's a good 50% increase for most games but considering the card contains twice the processing power it's reasonable to hope for more.
This is potentially both a good and a bad thing as it means there could still be performance to be gleaned from the card through a bit more optimisation. On the flip side, however, this could be as good as it gets, in which case it's difficult to recommend the HD 3870 X2 on performance alone, which is why it's lucky for ATI we also take into account price in our evaluation.
With 8800 Ultras still demanding the best part of £400, the HD 3870 X2 is actually a good wedge cheaper - certainly there's enough of a saving to buy yourself a couple of games. This brings it more in line with the 8800 GTX which, although not tested in all these games, is generally around ten percent slower than the Ultra in any given game. With this in mind, the HD 3870 X2 suddenly becomes a much more tempting proposition. Moreover, the extra multimedia functionality of the X2 certainly puts it ahead of either the GTX or Ultra.
That said, we still wouldn't out and out recommend you go out and buy the HD 3870 X2 because there's just a nagging doubt in the back of our minds that, no matter how much ATI assures us, driver support for the latest and greatest games or for more obscure titles is going to be slow to arrive, if it ever does. Sure, if you have a spare £300, you are in the market for a graphics card, and you don't already have a 8800 GTX or 8800 Ultra, then the X2 would be a good purchase but if you're a bit hard up, it's probably not worth losing any limbs over.
The ATI HD3870 X2 is probably the most convincing example of multi-GPU on a single card we've ever seen with it often beating the long standing performance champion, the nVidia 8800 Ultra. However the heavy reliance on after market support and co-operation from games and driver developers means there's always going to be the risk the latest games won't play nice with this card. So, for that reason we can't unreservedly recommend it.