NVIDIA GeForce 6800 Ultra: The Next Step Forward

Power Requirements

Current generation graphics cards are near the limit for how much current they are allowed to pull from one connection. So, of course, the solution is to add a second power connection to the card. That's right, the GeForce 6800 Ultra requires two independent connections to the power supply. The lines could probably be connected to a fan with no problem, but each line should really be free of any other connection.

Of course, this is a bit of an inconvenience for people who (like the writer of this article) have 4 or more drives connected to their PCs. Power connections are a limited resource in PCs, and this certainly doesn't help. Of course, it might just be worth it. We'll only make you wait a little longer to find out.

The card doesn't necessarily max out both lines (and we are looking into measuring the amperage the cards draw), but, NVIDIA indicated (in the reviewers guide with which we were supplied) that we should use a 480W power supply in conjunction with the 6800 Ultra.

There are a couple factors at work here. First, obviously, the card needs a good amount of power. Second, power supplies generally partition the power they deliver. If you look on the side of a power supply, you'll see a list of voltage rails and amperages. The wattage ratings on a power supply usually indicate (for marketing purposes) the maximum wattage they could supply if the maximum current allowed was drawn on each line. It is not possible to draw all 350 watts of a 350 watt power supply across one connection (or even one rail). NVIDIA indicated that their card needs a stable 12 volt rail, but that generally power supplies offer a large portion of their 12 volt amperage to the motherboard (since the motherboard draws the most power in the system on all rails).

Many people have been worried about heat generated by a card that requires two power connections. Just to be clear, we aren't drawing twice the power because we have twice the connection, nor are we generating twice as much heat. It's a larger chip, it draws more power, but it won't be clocked as high (with the 6800 Ultra version coming in at 400MHz as opposed to the 5950's 475MHz).

Customers who end up buying this card will most likely need to upgrade their power supply as well. Obviously this isn't an optimal solution, and it will turn some people off. But, to those who like the performance numbers, it may be worth the investment. And there are obviously rumors circulating the net about ATI's next generation solution as well, but we will have to wait and see how they tackle the power problem in a few weeks.