I have just assembled a PC - mobo is gigabyte 8SQ800- CPU P4 2.4ghz, The vid card is 128mb 8X. The PC works fine, but then, after ten minutes or so, the power supply just stops! I have noticed it tends to to this when I try hard core graphics. I have a 400W Q-Tec low noise temp-controlled PSU. What would you guys do in this situation?

Dave S
London, UK.

You might explain what you mean by 'the power supply just stops' a little better. But anyway, I think I know where your problem may be.

Those Q-Tec PSUs are not really suitable for most modern PCs because they only supply around 14 Amps on the +12v line. In fact, even the 550w version maxes out at 14A (that's so low that they don't even state this figure on their website - around 20A would be prefered, check the label on the PSU). What is probably happening in your system is that the PSU is overheating (as its having to work very hard to meet the power requirements of your PC - which increases when playing hard core graphics, as you said) and then shutting down to prevent failure.

Its a common problem that users buy PSUs based on the quoted wattage rating, but saving money on a cheap PSU is generaly a bad idea. You're probably going to have to buy a better brand name PSU such as from Enermax or Antec (400w or more prefered, though 350w would suffice) and put this down to experience. If you are lucky, you might be able to take that PSU back and swap it for something better.

Have a look at this thread ...

Power Supply Concerns

thanks`

Thanks Nic,

I should have been more specific. It basically just turns off without rebooting. If I press the power on button, it will boot up again, but only for another 10 minutes or so before it turns itself off again.

I will try an alternative PSU and see if it solves the problem - what would you reccomend?

Dave

An Enermax PSU with 350w or above would be adequate enough. They produced reliable and good PSUs.

Just ensure that any psu that you buy has at least 20A on the +12v line. The Enermax models are very good, though expensive, and are available from www.scan.co.uk who are the main uk distributers for Enermax.

Enermax 350w (26A@+12v) - Model: EG365AX-VE(G)(W) FMA

or, preferably the 450w model (shown on the same page), 33A@+12v. [much better than that 14A@+12v Q-Tech]

Thanks Nik,

last night I tried a 300w PSU with 16a on the 12v line - problem disappeared. Thanks for your valuable advice. I will use it until my
Enermax one arrives.

A point to make though - it is bad that Q-Tec distribute PSU's with high Wattages and super low current ratings.

I also bought a case off them and had to send it back. It was so flimsy and the edges/catchings were easily bent. It was clearly made very cheaply.

I would suggest people avoid this company's crappy products.

Dave.

Those Q-Tech PSUs are good quality, and are also well made, and most of all cheap (and very popular). They are also quite adequate for business PCs, budget family PC's, and any PC that would have been manufactured about 2 years ago.

However, these cheap PSUs are not suitable for enthusiasts (power users, and those that seek performance, or even many of todays PCs), and it is very misleading that they are advertised with such high wattage rating, as this implies that they are up to any task. This misrepresentation is common with cheap PSUs, and like any product, quality costs money.

Stick with top brands are you won't go far wrong, though ideally you still need to know what to look for when buying (even *some* quality 'Antec' brand 400w PSUs only have 18A@+12v, and Antec is a highly regarded brand), and match your choice to the power requirements of your system.

Note that not all 300w PSUs are created equal, and some have been known to output as low as 120w, due to inefficient power conversion and phase shifting of output voltage/current (please excuse the jargon). Better PSU's are often labelled 'PFC', which stands for Power Factor Correction, a method to correct the voltage/current phase shifts and so make more of the power available to the load (your PC).

Good to hear that you have finally solved your problem.