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Not enough power?

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Last response: in Components
June 3, 2003 1:47:03 PM


I've been having an annoying problem recently, which seems have to have got worse since I installed a Radeon 9700 Pro video card.

If my machine is doing anything graphically intensive (games, video editing etc), after 20-30 mins it shuts off as if the plug has been pulled out of the socket. The only way I can restart is by taking the plug out of the wall and putting it back in. Pressing the power switch has no effect until I do this.

I tried cleaning all the fans inside the case to make sure it's not a overheating problem. My temps don't seem to be too bad (Case: 30°, CPU 52° at load).

I have a Q-Tec 400w Dual Fan power supply, and I'm beginning to wonder if this is the cause of the problem (not enough juice?).

I understand the 9700 Pro is quite a power-hungry card and maybe this is proving too much for PSU? The same thing used to happen occasionally with a GF3 Ti 200 installed, but not half as often.

My current system specs are:

Athlon XP 2000+
Epox 8K5A2+ mobo
512Mb PC2700 memory
Radeon 9700 Pro graphics
Soundblaster Live 1024
Seagate Barracuda IV 80Gb
Lite-on CD-RW (48x12x48x)

Appreciate any advice

<P ID="edit"><FONT SIZE=-1><EM>Edited by BoBo67 on 06/03/03 09:57 AM.</EM></FONT></P>

More about : power

June 3, 2003 2:22:57 PM

I have the same card and I did have problems because of an insufficient PSU (250W), but I addressed this by getting an Emermax Silent Plus 460W PSU.

In theory 400W should be more than enough for your set-up, but you do seem to have a power problem rather than a graphics or overheating problem. I don't know how good Q-Tec PSUs are, but my initial thoughts are that you might be getting fluctuations in the voltages caused by a dodgy PSU - I could be wrong.

How old is that PSU? Any chance you could borrow another one to put in your PC for a few days?

:eek:  My PC is so wonderful it makes Svol seem less than perfect :eek: 
June 3, 2003 3:26:37 PM

The PSU is 5 months old, but the problem started a couple of months ago.

Another strange thing is when the machine has been shut down and unplugged for half an hour or so, it switches on as soon as I plug it back into the socket. I don't have to touch the power switch. I read that this can sometimes happen with cheap power supplies.
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June 3, 2003 3:44:58 PM

Most people might not recognise that problem as normally people just leave their machines plugged in, although of course in your case you need to unplug occassionally because of your problems.

I know that a 400W cheap PSU cannot deliver the same performance as a 400W Antec or Enermax, particularly under heavy loads. You've got a reasonably hefty computer so 400W is probably the least I'd recommend, and if it's a poor quality PSU then it might not be able to take everything you throw at it.

The other thought that occurred to me is that the PSU might conceivably be overheating and doing a safety shutdown, although a shutdown due to overloading seems more likely. Does it have dual fans? It probably doesn't have a temperature monitor, so the best you can do is try to gauge how hot the exhausted air is. Not very scientific though.

If it's 5 months old then it should be under warranty, I'd see can you RMA it. It's difficult to test a PSU unless you have the right equipment.

Just out of curiosity, do you get an improper shutdown procedure when you reboot the machine?

:eek:  My PC is so wonderful it makes Svol seem less than perfect :eek: 
June 3, 2003 4:14:08 PM

No messages appear on reboot. Seems to boot up normally.

I can't RMA the supply because I opened the case to clean the fans to make sure it wasn't overheating. Bit risky I know, but I made sure I didn't touch anything inside. I also figured that seeing it's 5 months old and only cost £30 (€42?) that it wouldn't be worth sending back anyway.

I have read reviews of this PSU that said the heatsinks are very small for a supply rated at 400w, so it could be a problem with overheating. It's very lightweight too.

Think I'll be ordering a new one soon...Enermax or Antec I think.
June 4, 2003 8:21:27 AM

That would explain a lot. And at that price, I'd be surprised if it wasn't anything more than a cheapo generic PSU.

I just spent €110 on a 460W Enermax Silent Plus, it's a fabulous PSU and has solved a lot of the 'problems' my PC had. It's worth the investment, and you won't go wrong with Antec or Enermax. I'd go for at least a 430W though, more if you can afford it.

:eek:  My PC is so wonderful it makes Svol seem less than perfect :eek: 
June 4, 2003 11:55:40 AM

I ordered a new PSU yesterday. Went for Antec Truepower 430W. Hopefully that should stop the problem I'm getting. I'll let you know how I get on when it arrives.
June 4, 2003 12:42:15 PM

Good call. Hope it works out for you.

:eek:  My PC is so wonderful it makes Svol seem less than perfect :eek: 
June 8, 2003 10:50:16 PM

you mentioned voltage fluctuations earlier on, Windging is that normal on games and such or should voltages stay rock solid with a good PSU?
June 9, 2003 2:43:11 AM

Power fluctuations shouldn't vary by more than around 5%. I use Fortron power supplies to avoid such problems, they are both better and cheaper than Antec.

<font color=blue>Watts mean squat if you don't have quality!</font color=blue>
June 9, 2003 9:41:45 AM

Voltages can fluctuate if you have a crappy PSU. It's not limited to when you're playing games, but the effects are more evident when your PC is under load. A good PSU will control voltages carefully and ensure that very tight tolerances are maintained.

:eek:  My PC is so wonderful it makes Svol seem less than perfect :eek: