powered by a 500w PSU (cheap brand)
You may have answered your own question.
When I use the eXtreme PSU Calculator Lite to figure out your power requirements, and setting the values for worse case scenarios (to allow for overclocking and headroom) by setting the board to high end, CPU utilization to 100%, system load to 100% and capacitor aging to 30%, and two regular 120mm fans, I get 470W - and that's not overclocking. You did not specify which 8800GT you have but according to BFG
, theirs requires 425W with 28A on the 12V rail minimum
. And that's with one graphics card.
You already admitted this is a cheap supply. PSUs get weaker over time (hence the capacitor aging value). And even if your requirements fall under 500W, it is just under - meaning the PSU is hustling full time all the time. That's 3 strikes there. If you are not using a UPS with AVR, then you are feeding your PSU and computer dirty power - ALL computers need to be on UPS with AVR, automatic voltage regulation. Feed your supply clean power - with a good PSU with AVR.
Do not use a cheap PSU. I typically put it this way. Would you buy a fancy new Porsche, then dump off-brand, generic gas from the QuickyMart in it? Maybe you would, but would you expect it run at peak performance? A car engine can miss a beat and keep running. Not so with digital electronics.
Here's my canned text on picking out a new PSU.
Use the eXtreme PSU Calculator Lite
to determine your power supply unit (PSU) requirements. Plug in all the hardware you think you might have in 2 or 3 years (extra drives, bigger or 2nd video card, more RAM, etc.). Be sure to read and heed the notes at the bottom of the page. I recommend setting Capacitor Aging to 30%, and if you participate in distributive computing projects (e.g. BOINC or Folding@Home), I recommend setting TDP and System Load to 100%. Research your video card and pay particular attention to the power supply requirements for your card listed on your video card maker's website. If not listed, check a comparable card (same graphics engine and RAM) from a different maker. The key specifications, in order of importance are:
- Current (amperage or amps) on the +12V rail,
- Total wattage.
Then look for power supply brands listed under the "Good" column of PC Mechanic's PSU Reference List
. Ensure the supplied amperage on the +12V rails of your chosen PSU meets the requirements of your video card. Don't try to save a few dollars by getting a cheap supply. Digital electronics, including CPUs, RAM, and today's advanced graphics cards, need clean, stable power. A good, well chosen supply will provide years of service and upgrade wiggle room. I strongly recommend you pick a supply with an efficiency rating equal to, or greater than 80%. Look for the 80 Plus - EnergyStar Compliant
label. And don't forget to budget for a good UPS with AVR (automatic voltage regulation).