Fan problem

[NixD]

Ok, to start, here are my specs:

AMD X2 4400+ 2.2ghz
2x512mb RAM
256mb 7800GTX
480w PSU (which I believe may be the problem)

I built this computer around half a year ago, and for the first 3 or 4 months I had no problem whatsoever when playing games. However now when I play source based games (well Counter-Strike: Source anyway, and possibly other games but that was the main game which I was playing when I first started noticing the problem), after about 10 minutes I notice one of my case fans (I have 2) starts to slow down. At first I thought I could of just been imagining it, but when I saw the fan had completly stopped I knew there was a problem.

I stopped playing for a while (due to that and I seemed to be busier in general) but after about 2 months of not playing I encountered the same problem; I switched off my computer, and when turning it on, the fan didn't move at all and then after about 10 seconds decided to finally move....that was when I decided to just unplug that fan. Though when playing a bit of CSS for 10 minutes, the remaining fan decided to slow down...

Now for some reason I believe it is the PSU, although I'm not paticulaly sure....I built this PC (first time, so a newbie) and had a problem with the PSU and thought I'd have to purchase a new one. I'm probably the worst person to explain this, but there were too many little holes on that ATX power connector for the actually connector, resulting in 4 extra holes when plugging in the ATX power cable (if that's what you call it?).

When we got a man at our local computer shop, who I don't actually personally trust much, to see if everything's ok, he plugged another cable somewhere else when seeing there were four missing holes, and said it should be fine.

So is it actually fine? Is there a connection between the fan slowing down and this incident with the PSU?

Thanks

[ultim8um]

Doubtful that its the PSU tbh... Especially if the fans are being run off the board itself rather than directly off the PSU?

If the voltages to the fans are going down or being pulsed then thats down to the motherboard / software controlling the fan speeds e.g. MBM etc.

[teachmech]

It sounds like you have an older psu that has a 20 pin connector not a newer 24 pin connector. Newer psu have seperate power rails of the 12 volt one for cpu and one for the rest.
If you have access to a newer psu try it and is if the problem reoccurs, it could be that you have been lucky to run it this long without a correct power connection.

[ultim8um]

If your fans were spinning down then everything on the same 12 volt rail would be affected and I am fairly sure that the speed of your fans would be the last of your worries lol

Re reading your original post I now see that you have a newer board with an older PSU. It sounds like you hadn't plugged in the additional ATX power cable (4 pin in a square arrangement, yellow and black cables normally). This is probably what the guy in the local PC shop did. You can sometimes get away without this, it all depends on what kit you have plugged into and drawing power from the motherboard.