I already have a 500W decent one, I need more power. Amperes and watts!
A "decent"500w unit will run just about any single video card out there since most have 34a+ on their 12v. you are upgrading to 650w unit that probably has around 38-40a on the 12v. that's really not a power upgrade.
what is your current PSU, what are your PC specs (CPU & GPU) and why are you upgrading?
Biostar TA770E AM2+ motherboard
AMD64 AthlonII 240 X2 (2.8GHz) AM3 processor
2GB Crucial DDR2 800MHz memory
CiT 500w (+12V1 = 14A, +12V2 = 13A) PSU
CiT 1008 Piano-Black Midi-ATX case
160GB SATA2 3.5" 7200rpm
I have no graphics card right now, that's the reason I'm upgrading my PSU. I want to be able to run a HD5670 or HD5770 but was told that my PSU certainly won't run one of those cards.
that's not a great PSU but the ATI 5670 hardly needs much power. most generic 300w units will power the ATI 5670 and most generic 400w will power the ATI 5770.
while purchasing a quality PSU is always a very good investment, your current unit will power an ATI 5670...and probably power the ATI 5770 since your CPU hardly draws any power. You won't break 300w at load with either card.
you can purchase the ATI 5770 and run it with your current PSU while saving for a new one (like the ocz linked above)
Core i7 Test System Specs
- Intel Core i7 965 Extreme Edition(Overclocked @ 3.70GHz)
- x3 2GB G.Skill DDR3 PC3-12800 (CAS 9-9-9-24)
- Asus P6T Deluxe (Intel X58)
Okay what about the amperes? I only have a total of 27A between 2 rails?
you have one 12v rail that has been split. you don't add the two splits together, you need to see what the total watts on the rail are to figure out the amps. My guess, your 12v rail is around 25a. that's if the PSU can actually provide the power it claims it can.