The Protein Computer PSU Calculator.
Start with a bog-standard cheapish but at least half-decent PSU. If you are not sure what that is, pick it up. If it has no particular weight in your hand, it's decent. If it seems a bit light, it's half-decent. If it seems really light, it's carp - throw it away. Good ones cost real money and are always heavy. There are only four sorts of power supply:
- Carp
- Half-decent
- Decent
- Good
Now, ask yourself ....
1: Does the system have:
- Multiple drives (more than three - HDD or DVD, both count)
- Large graphics card (needs large heat sink and/or cost over $200 when new)
- Large graphics card (as above)
- Very power-hungry CPU
- Higher than typical reliability requirement
- Weird add-on stuff that chews juice
If you answered YES once, you can get away with a CARP PSU but you should have a HALF-DECENT unit.
If you answered YES twice, you can get away with a HALF-DECENT PSU but you should have a DECENT unit.
If you answered YES three times, you can get away with a DECENT PSU but you should certainly consider a GOOD unit.
If you answered YES more than three times, you won't get away with a DECENT PSU, you absolutely must have a GOOD unit.
Note: yes, you ask the graphics card question twice and count the answer twice.
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There you go: one reliable, accurate Power Supply Calculator, free to any good home, guaranteed 100% Javascript-free, runs just fine on any brain-equipped human.