HI all i am currently running a C2D e7400 4 gb ddr2 800 mhz ram and a sapphire 4670 1 gb edition and a 320 gb WD HDD my PSU is 400W and it gives 12 amps on the 12 v rail is it enough any help wold be highly appreciated
Generally, you want your power supply to deliver more than your required wattage to account for PSU inefficiencies. Some technical help sites and forums suggest up to 50%, though it's up to you how much of a safety blanket you want .
Generally, you want your power supply to deliver a lot more than your required wattage to account for PSU inefficiencies. Newegg suggests a PSU that delivers twice what you need. It's up to you to follow that advice or not.
Does NewEgg actually say that? Double what you actually need?
I thought they did, but I went back and checked and couldn't find it. I've been searching so many web sites in the last week, especially about PSUs, appeared on one of them. Though, when I did another internet search I found this thread:
It seems as though you like the 70-85% full-load/30-50% idle figures. I guess it all comes down to preference and balancing the "Having too much power and being super safe" ideals with "Choosing a model closer to your own power draw to be more efficient".
All I can go on now is my own experience. That experience says I bought a replacement PSU too close to the estimated power demands and it doesn't work. Personally though, I think the OP would be fine with a 400W-500W supply since doubling it and going for 700-800W seems a little overkill.
I'll edit the original post to fix the citation error
The quality of the PSU is every bit (and maybe more important) than the quantity of power it's rated to provide.
We like to see PSU's torture tested to 100% of its rated capacity by the better review sites like JonnyGuru, HardOCP, HardwareSecrets and a few others. If you get a top rated PSU from one of those sites it's less of an issue if someone looks to be nearing 80% capacity.
Since the OP's system is going to pull less than 200watts DC, maybe 260watts AC if his PSU is 70% efficient a good 400W PSU is certainly generous. Of course we're guessing since we don't know what that 12amp +12v PSU is. Personally, I'm thinking it might be some type of dual +12 PSU.