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How much Power do I need?

post #1 of 6
Thread Starter 
salutations all...

I am looking to buy a new PSU for my system.

Very recently my computer has been failing to post when powered on (fans all spin etc), having swapped motherboards, tried another CPU, tested RAM and tried another Graphics card - all resulting in the same problem, I am left to believe that it is the PSU causing the issue.
This seems reasonable as I can get the computer to boot properly if I run it with minimal components installed, PCI cards out, DVD drives unplugged etc.

Anyhow, that being the case i am wondering what wattage PSU I should really be looking at to replace the unit I have.

The current PSU I have is an OCZ StealthXStream 600, just over 3 years old (gggr!!), but I think that 600W might be overkill to be honest.

Also, I am confused because I read that my graphics card requires 24Amps on the 12V rail and many PSU's I see don't supply this. In fact the OCZ supply I currently use is rated only 18A?

Here are my system specs:

2 x 1GB DDR2 800
Zotac Nvidia 8800GT AMP
PCI Wireless card - Tenda N300 I think
PCI soundblaster Audigy ZS - with front bay
USB Wireless Keyboard
USB Mouse
1 x 90mm Case fan
1 x 120mm Case fan
2 x SATA Hard disks
1 x SATA DVD Burner

I think thats about it. I don't overclock, but might do if I can get my bloody system stable!

Any comments would be much appreciated.
post #2 of 6
Any half-decent 300W really.
post #3 of 6
Thread Starter 

Seriously, that low? Most PSU calculators seem to suggest around 315W.

Any comments regarding the 12v Rail?
post #4 of 6
nVidia's amperage requirement accounts for the entire system, not just the video card. Get yourself a Corsair CX430 V2, it's cheap, it's good for the price, and it'll be more than enough for your system.
Note that your current PSU has several rails at 18A, not just one, and it balances the load between however many you have (I think it's 4 on your unit?).
So I don't know if your problems stem from your PSU, but the aforementioned Corsair CX430 V2 will be perfect for you
post #5 of 6
Thread Starter 
Thanks for clearing that up, it makes sense now.

As for my PC problems, well I just don't know what else could be causing it to POST/boot sometimes and not the other times?
Like I said, I have tried different graphics cards, CPU's and even bought a new motherboard. The more I load the mobo with my pci cards and drives, the less able I am to get the machine to boot.

With only 2 Hard disks, RAM and the CPU its just about 50/50 whether it starts or not.
Haven't seen any freeze ups or reboots in windows either, even whilst playing Crysis warhead.

Oh, forgot to mention. All of this started when my first Audigy 2 ZS card died. It no longer work now, so bought a replacement, which in turn was causing my PC not to boot when plugged in (tested in another machine, fine). Since then the issue has been gradually getting worse.
Hence why I thought it was the PSU that is causing the issues.

I do hope I am right, but I'm not so confident in these areas..
post #6 of 6
Thread Starter 
Anyways, I'm going to go with that it is a PSU problem. Its the last common denominator...

How does the Corsair TX650 sound for my system?
Gives me some room for upgrades, and is quite nicely priced unit with 5 year warranty!
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