Not exactly. It depends a lot on the rest of the system, and those "requirements" are extra high, because NVidia and ATI want to cover their asses and be absolutely sure people have good enough PSU's.

My brother recently bought an Athlon 64 3500+ and Geforce 7800 GT, and hooked it up to his old no-name 350W PSU. Runs without a hitch.

Edit: But of course you should have a decent quality PSU no matter what. I'm just saying the wattage they usually claim to require is overrated

[Edited by - Spoonbender on November 3, 2005 2:55:38 PM]

More important than the wattage of your power supply is the quaity. A high-quality power supply will deliver plenty of power at each of the different voltages required and the power will be 'clean'(ie constant DC with very little noise) while a low-quality supply will deliver too much power at the voltages that aren't used much and not enough at the voltages used a lot, the will deliver voltages quite far from the proper value (the standards give a lot of room for differences, not sure on actual values but for ex maybe +5V can really be +4V to +6V - high quality will be like 4.9 to 5.1 varying because of temperature/line power/etc very little while low quality will be 4.5 to 6.5 varying randomly), and the power provided will have a lot of noise and small spikes and dips.

Both will work 'fine' for low-demand machines (though low-quality supplies put some strain on the electronics), but for high-demand machines you need either a very high wattage low-quality part (if it says it can supply 500W, you can probably count on it for MAYBE 400W using a decent measurement setup), or a decently rated high-quality part (if it says 400W you can count on it providing 400W).

Most systems don't need a lot of power, but use high wattage low-quality supplies because they're cheaper. If you can afford it, a quality power supply is a good investment because you can keep it in your newest machine whenever you upgrade and get less expensive parts to take it's place in your old machines (since you probably don't care as much about them).

You can find decent reviews of power supplies on many hardware websites, such as Anandtech.com:
http://search.anandtech.com/search?q=power+supply&site=atweb_collection&client=atweb_collection&proxystylesheet=atweb_collection&output=xml_no_dtd

-Extrarius

Everyone should be careful about saying things like:

"X is the best mainstream card there is."

This is up for serious debate. Better to say, "I've used X, and it's worked well for me, but lots of people have nice things to say about Y as well."

Personally I think if you want to get serious, you need more than one development machine, and more than one brand of video card. Maybe NVIDIA does better with OpenGL, but wouldn't that mean if you made your game sing with ATI first - that it would be easy enough to adjust for NVIDIA - and then you would maximize your market?

I don't know... just saying that there is more than a single point of view here, and brand loyalty is a sure way to miss out on important views.

Both the X700 and the 6600GT run under $200. Both seem reasonable to me.