Based on the Dailytech architecture, the 8800GTX consumes about as much as the X1950XTX. Now, the cardinal question is what 'load' constitutes. Is there any graphic utility that can properly 'load' an 8800GTX to the max? I would dare say not, given that the DX10 functionality is NOT used yet.
The main thing that puzzles me to no end though is this:
The marketing material included with the card claims NVIDIA requires at least a 450W power supply for a single GeForce 8800GTX, and 400W for the 8800GTS…GeForce 8800 cards in SLI mode will likely carry a power supply "recommendation" of 800W. NVIDIA's GeForce 7950GX2, currently the company's top performing video card, carries a recommendation of 400W to run the card in single-card mode.
Why would 450W for one card be enough and 800W be required for SLI? What am I missing?
Given the 450W recommendation for a single card, and 800W for SLI, I think there are certain functionalities that cannot be used by a single card (just like certain types of AA that can only be used in Crossfire with X1900's). The 350W hike seems a lot, indicating that the additional card DOES require a lot of power. However, nVidia probably takes into account that a good 450W PSU has like ~32A on the 12V Rails and that a 800W might only have ~50A or so (quality ones will have more, but it might be nVidia plays it safe)