(Help a Newbie) PSU Questions

[JE78]

I'm fairly new to PSU's so forgive me if I ask some stupid questions and yes I read the sticky at the top of the page. I upgraded my video card from a ATI 9000 Pro to a ATI 9800 Pro over the weekend. I removed all the old drivers and installed the CAT 4.9's. At first I couldn't get get the option of 8x APG but after upgrading the motherboard drivers I could enable it and thats when I started having problems. When the card is on 8x APG I can't play a game, or even have a windows session for 20 mins before my system locks up but as soon as I switch it back to 4x APG I can play for hours and not have a problem. I've been posting this problem on a few message boards and people seem to think its a PSU problem. But if its a PSU problem then my system shouldn't even turn on right? Here are my system specs:

P4 2.53 GHz
512mb PC2700
WD 200GB, Maxtor 60GB both at 7200 rpm
DVD-RW
DVD-ROM
Sound Blaster Live 5.1
9800 Pro CAT 4.9 drivers (tried 4.10 no difference)
9000 Pro previous video card
350 watt PowerUp PSU
Motherboard: http://www.giga-byte.com/Motherboar...s_GA-8SG667.htm

Also if it is the PSU that giving me problems i've been looking at replacemnts and wanted to know what was wrong with Thurmaltake PSU's? I've been looking at these 2. http://www.newegg.com/app/viewproductdesc.asp?description=17-153-006&DEPA=0
http://www.newegg.com/app/ViewProductDesc.asp?description=17-153-007&depa=0

But everyone says to get a Antec, or Erenermax or Fortron. So then I started looking at these http://www.newegg.com/app/ViewProductDesc.asp?description=17-103-908&depa=0
http://www.newegg.com/app/ViewProductDesc.asp?description=17-104-968&depa=0

But they are a bit more than I have to spend. Any information on my problem and help on choosing a PSU would be appreciated. Thanks.

 

[Ice Czar]

I But if its a PSU problem then my system shouldn't even turn on right? .

nope power issues are actually some of the most intermittent there are
largely because of all the variables, components only draw there full rated load when they need to, review > http://hardforum.com/showthread.php?t=823481

come back with the amps the caculator comes up with for your assorted rails
and we'll talk about the assorted tradeoffs

if its not a power issue
and its not a driver issue
its likely a thermal issue

none of the above generally means something has degraded
generally simple enough to isolate by crossparting

 

[JE78]

Here is what I came up with:

3.3v = 2.7
5v = 13.9
12v = 14.7
3.3v + 5v = 78.9
3.3 + 5 + 12V combined MAX = 256
total output = 256

There were a few things like fans and CPU fan i wasn't sure about so I guessed. Let me know what you think.