FUD Zilla has some intel on why NVIDIA delayed the GeForce 9800 GX2 dual-GPU graphics card to March. The site claims the heat produced by the 250W TDP chip is one of the big problems and that NVIDIA isn't realy happy yet about the SLI scaling:
The retail / etail market expect that this card will be hot and as long as it runs stable the market shouldn’t care about it. Yeah, it's not the first time that we will be telling you that the Geforce 9800 GX2 is one hot card.
More importantly is the fact that Nvidia isn't happy with the performance scaling of two of these cards together. Yes, Nvidia will kill 3-Way SLI and reintroduce Quad SLI with two of these cards but it needs to squeeze a bit more performance, otherwise it will be the Geforce 7950 GX2 performance fiasco all over again.
This was enough to push the card back a few more weeks and currently the Radeon 3870 X2 definitely looks even more attractive at its €350 retail price.