ThoughtsThe ASUS Extreme N7800GT Dual is definitely one of the more intriguing graphics products to hit retail in the last half decade. Multiple GPUs on one board is something that usually doesn't come out quite right, but the Dual certainly gets it more right than wrong. NVIDIA SLI technology takes away many of the risks inherent to doing so, with a robust implementation of a multi-GPU rendering system using PCI Express.
When the CPU isn't the limiting factor and, crucially, SLI is able to accelerate the game or application, the product simply flies. As a single board product, the Extreme N7800GT Dual has no performance peer. It's as fast as anything else when the CPU is the limiter and pulls ahead of single GPU products without much fuss when it's not. The performance really wasn't in question when conditions are right to show it off. G70 lacks some of the image quality possible in recent ATI Radeons, though, dampening the appeal of the latest NVIDIA GPUs and therefore all products based on them. It's not all about performance these days, after all.
As an engineering showcase and just as a cool piece of hardware, the Extreme N7800GT Dual presses all the right buttons. The PCB design on its own is worth a separate article, the issues you have when supplying power to two GPUs from a single power input and the layout issues to overcome are fascinating in their own right and in that respect, ASUS's engineers responsible for the card should be proud.
The larger issues with the product are in terms of size, price and availability. It simply won't fit in a large number of cases, it'll cost £615 including VAT in the UK on launch and while you'll get Call of Duty 2 with it, that's not nearly enough to cancel out the near £200 difference between the Dual and a pair of regular 7800 GTs in SLI. And with only 2000 pieces produced, getting your hands on one might be hard.
In terms of fan noise, there's no more noise when the fan's at full speed than the recently introduced ATI Radeon X1800 XT but it's certainly louder than a reference GeForce 7800 GTX or GT. Under our testing, the fan never seemed to get above ~80% even under load and idle noise was very acceptable.
My instinct tells me that it'll sell out regardless of that huge price delta simply because it's rare, desirable hardware, but I honestly can't recommend one over the flexibility and huge wallet savings a pair of regular boards will get you. And that's coming from a reviewer with a fetish for collecting rare 3D hardware. I look forward to collecting one in a few years, but I wouldn't fork out £600 for one right now.
Very hard to judge since it's such a limited edition, very very expensive boutique piece of hardware. Excellent performance and engineering prowess, but more than a little bit nuts in every other way.