PSU Wattage Too Low?

Hi,

Just build a new system on a Gigabyte GA-VM900M M/B, Pentium 4 3.0GHz CPU, 2 SATA drives, 1 DVD recorder, and two 1Gb DDR2 RAM modules. The PSU is rated at 300 watts, 350 watts max.

The system worked fine, but then I decided to replace the noisy case generic case fan (12V, 0.28A) with a Thermatake (variable speed) Smart Case Fan 12V, 0.40A). With this fan hooked up, the computer will not start. The front light flashes briefly, but that's it. So after waiting a while, I reset the CMOS, installl the generic case fan and all is OK.

So should I upgrade the PSU (and if so, to what), or is there probably a defect in the Thermatake fan that is causing problems?

Thanks for any advice.

I went a P4 because I'm only going to use the PC for email and internet access. I'm taking my main work PC (this one - an Opteron 165) off the net so that I don't have slowdowns with Nortons and continual Windows updates (half of which don't even install anymore).

Do people think that the variable speed control on the Thermaltake is maybe the problem, rather than the PSU?

I know some fans allow you to plug up other devices through them, but they don't have all four wires for the other device to connect. IE. maybe a 12V and ground or something like that without any of the other voltages. So if you have other things plugged up through the fan that could be the problem. What I would do is unplug the fan and make sure everything else boots. You know the fan bing possible 3w more than the previous one isn't going to keep the system from booting, since it's such a small increase.