250w is too less!!
I'm useing an 350W with my normal Athlon Xp Mobile System and it gets Hot
Try to get an 350 and more unless you wouldn't like to burn your System and everything elese!
Even if it's an fanless one more efficent than 80% it will be lacking your System under full load and when you are overclocking.
In addition it might be weak in combined power and your system will be unstable (I've got 180 combined power as it's said on my PSU for my System but to my Signature you might add my usb Devices and all othe pci cards, not listed Drives)
Read the Text and the blue one on the bottom!!
Let's sum up what we have learned from this simple test:
* All power supplies with the same power ratings are not the same. This is obvious since only one of two 300 watt power supplies could actually get the computer to boot properly.
* Total power ratings may actually be a very bad indicator of the quality of the supply. In my opinion, we should look at the combined 3.3v/5v power ratings instead. These ratings are displayed on every ATX PSU. You can check for this by looking on the amperage rating chart on the PSU. Somewhere on that chart it will tell the 3.3/5v combined power rating.
* Do not buy a power supply you have never heard of. Buy a high quality unit with a good reputation such as SparklePower, Enermax., and Antec.
All said, btw Please Post details about you 200W PSU! Like V and A