First and foremost, I bought THIS today with the intent on using it in my latest gaming build. It's rated at 500W and is "SLI Certified/Xfire ready", but from my experience the rating is usually a little higher than what a PSU is actually going to put out. I was intending on putting a single Radeon HD 5850 as my video card as it fits my price point, but after reading the 5850 review, under a full load it's rated at sucking a little over 300W by itself (the 5830 being rated at *half* that power consumption, but that card is a whole separate demon to discuss), leading me to worry that assuming the PSU actually tops out at maybe 450W average, a little less than 150W isn't going to cover the CPU and everything else.
As for my second issue, I'm looking at two CPUs here:
From the specs, they're *exactly* the same CPU, except one is rated at 95W, and the other is rated at 125W. They're also exactly the same price. My first reaction is that the 95W one is just a later revision of the chip that consumes less energy for the same performance, but by that line of thought I would expect the 125W to be a little less expensive, or at least the 95W to be a little more expensive. I feel like there's something i'm missing between the two.
Edit: To clarify, I don't intend on overclocking anything in this system, everything will be running at stock clock rates.
First off the 5850 only will use a max 150 160 watts under full load and that is running like benchmarks dureing gaming it will be much less and the cpu is the same like you said AMD just made a low power model its the same price get it less watts less heat. And your PSU will run that just fine.
I'm almost certain that the 5850 review was stating entire system power draw when they said 300watts, so the PSU should definitely be fine either way.
And the two CPUs are identical, power draw is probably just very little difference (probably not a full 30w). And the reason they're the same price is because no one really cares. I'm kinda surprised they're listed seperately.
The general rule of thumb is a high quality 500 to 550 watt power supply with sufficient current (amps) on the +12 volt rail(s) can easily power a system with any single video card made. A high quality 700 to 750 watt power supply with sufficient current (amps) on the +12 volt rail(s) can power a system with two video cards operating in dual mode. There are a few exceptions like the new ATI Radeon HD 5000 series cards which use less power due to their energy efficiency.
A high quality 500 to 550 watt psu will have a +12 volt rail rated at 40 amps. A high quality 700 to 750 watt psu will have a +12 volt rail rated at 60 amps.
In addition the power supply should be at least 80+ Bronze certified for energy efficiency. There are some models available which have achieved 80+ Silver and 80+ Gold Certifications.