Power Supply Issue

I have a 300W power supply and bought a cheap $20 480W from a local computer store. Installed it and when Windows appears my computer locks up. Tried 3 times. Stuck my old one back in, everything is fine. Took it back, exchanged for another one, same problem.

Is there anything at all I need to do besides plug and go? Should I be changing anything in the BIOS? Mother board? Maybe the power supplies I tried are complete junk.

Some cheap power supplies dont give a consistent supply of power to your motherboard and components. Its usually flaky cheap ones. Give em a weigh, I know it sounds weird but you can usually tell how good a power supply is by the weight of it. Higher weight means higher quality components/more capacitors etc.

What brand is this new power supply. Its suspicious how cheap you are getting it. Especially if its rated at 480w.

One thing that springs to mind is some modern graphics cards have their own power connector - have you got one that you have not connected?

My advice would be pretty much the same as Leiden. Don't buy cheap power supplies, ever. Ignore the wattage they state, it doesn't mean anything. It's like refresh time on an LCD, everyone measures differently and the cheap ones will still be junk despite the rating.

When you're buying a hard drive, a videocard, an optical drive, sure, go cheap, but don't go cheap with PSU's. But a quality brand like Thermaltake, Enermax, Coolermaster, Antec, OCZ, Tagan, Vantec.

Of course, if the unit you have already *is* one of those, then maybe you do have a problem connecting it, but since you reconnected the old one no problems, you seem to know what you're doing.

Make sure the supply switch at the back is set to the right setting.

I dont believe no matter how cheap a 480W Power supply is, that it would be worse than a cheap 300w power supply

I dont think the computer would ever power up if He had it set to 240V, take a looksie at the sticker on the side. Compare the ratings between the two power supplies. It may be higher wattage, but is it giving out the required Amperage for your system to operate?

For a 480W - 500W around 30 amps per rail (3.3V, 5V, 12V) is a good base. Another thing to look for is the amount of Watts per rail. You might have a high wattage on the 3.3V and 5V rails combined, but a low amount on the 12V rail -- or vice versa. In which case you may have the added P4 connector, which requires 12V and which generally powers the processor/agp/pci-e area of your motherboard.

Good guide, take a looksie: http://www.technibble.com/why-you-should-avoid-cheap-power-supplies/

Thermaltek are somewhat overpriced where I live -- albeit they are of a better quality. I would suggest Enermax or Coolermaster -- but then again its worth spending that extra buck for a good one.

Thanks all, everything is set correctly. Puki... yeah my 7600GS has a connector and it was connected. The second PS I had exchanged for actually got me into Windows, but the card was complaining that it wasn't getting enough power and starting spitting out error boxes back to back until my taskbar was filled with hundreds of them. I got what I paid for, and will be getting a refund today.

Leiden: It is very light. So light in fact that it doesn't feel right.

Lessoned learned, do NOT buy cheap power supplies!

I think the lesson here is that a 300W power supply is inadequate!

How many drives do you have in that system?

I've now got a 500 watt power supply in my system, which if I remember correctly is around 30-40 watts more than I calculated I'd need with one of those online watt calculators. I was running fine on a 480, but I just upgraded my CPU to a 4800+ AMD, got a case which has two cooling fans, and a few months back I added a couple SATA hard drives, so I was probably just squeaking by at that point on wattage. I didn't want to press my luck by trying to continue to use the 480. On the other hand, 500 isn't much of an upgrade is it? I just might take that back and get the 550. I need to calculate my wattage needs again.

Oh and when I upgraded the power supply I also had to upgrade the case because the power supply was blocking the CPU fan in the mini tower I had before. So I got [a http://www.coolermaster.com/index.php?LT=english&Language_s=2&url_place=product&p_serial=CAC-T05&other_title=+CAC-T05+Centurion%205]this one[/a] from coolermaster. It's a really cool case. In both meanings of the word. The drive bay covers are all vents with black foam behind so you don't see inside. And the side panel optionally comes without clear plastic and that has a vent directly to the cpu fan. Plus it has two case fans one on front and one on back. With the cpu fan replaced with a "silent" fan, and set to adjust according to temp, and a power supply which has a back fan that doesn't run when the power supply is cooled enough by the internal fan, this is a super quiet pc. (The reason I got the quiet cpu fan was the fan that came with the 4800+ sounded like a jet engine compared to my 3600+!) But the coolest feature of the case isn't the cooling ability of it. That's just a bonus. The coolest thing is the case doesn't require ANY screws to install PCI cards or hard drives! It's got plastic sliders with locks, and tabs you push down and lock to lock the stuff in place. And it works better than you'd think. Only a coupld drives gave me any trouble, but I was putting in 5 drives, so I had to install one in a bay intended for floppies, (there's like three slots for hard drives that work awesome, plus two floppy bays) and one I had to install in a 5 1/4 bay with adaptors and I had a hard time getting the adaptors which were not the full length of the drive, to lock in. But I got everything in there nice and solid in the end, and I had like 30 screws left over from the old tower I didn't need anymore. And now there's lots of space between the drives to keep them cool too. And the front case fan blows directly on them.

I get by with a 400W pretty fine, or at least it seems fine :P

AMD 3800 (~2.4GHz), 1.5GB DDR-400, 6600GT, 200GB HDD, DVD-RW. Pretty average system in terms of devices installed.