Problem with the computer, I believe it's my GPU

[deadeye93]

Ive probably read dozens of posts and threads regarding similar issues but i cant find the answer - and its driving me insane.

I bought a new pc about a year ago:
-3.0 core 2 duo (Intel)
-2gb ddr 800mhz (not OC)
-a good motherboard (i think? lol. its new too)
-nVidia GeForce 9800GT 1GB (which i believe to be the core problem of this)
-550W PSU

While playing games, the computer crashes, freezes or something like that, (the screen is like refreshing itself, but the image is the same - then the sound fails, and eventually it goes black) and the only way out of it is restarting. i get strange issues on different games (sometimes i get nice green pixels on some of the objects in shooters or X3TC(game)) but the bottom line is i cant play anything at all.

As i said, ive read about issues like that countless times and here is what ive done so far:
-monitoring:
-i checked the temperature of the core, gpu and both seem stable (gpu =48C, core =31C both on min load - on max gpu <70C, core <40C)
-i changed the gpu fan properties via RivaTuner
-i scaned the ram with memtest86+ (and it showed 0 errors!)
-tried to find a crashing point: its random: from 75 degrees C to 60 degrees..
-cleaning:
i obviously cleaned it out of dust (took 4 hours!)
-connections:
-all connections were checked, i get no problems or warnings from bios (no beeps etc..)

Im near desperate, and i already contacted the supplier.
any other suggestion before i throw that card into the face of the shop that sold it to me?

p.s. thanks to anyone who replies.. im very desperate..

 

[deadeye93]

Im not sure if thats anything important, but ive read the 12V output from the psu has to give around 30A to the gpu, while mine can give only 20A.. can this be a reason to crashes?

 

[Archean]

Voltage difference can cause it to behave oddly and I think if its under warranty there is no harm in sending your system to the vendor who sold it to you. Infact, in such situation it is the best way instead muddling around with hardware and ending up voiding your warranty accidentally.

 

[yangly18]

I've had a problem with my 9800 too, i still don't know whats wrong with it

 

[Archean]

what sort of problem?

 

[deadeye93]

Ive talked to some friends who understand in computers, and they think the amplage in the 12V is too small.
many middle grade PSU have dual outputs, most of them are 20A. 9800GT needs AT LEAST 30 ampers, thus, the card just doesnt get the power it needs

 

[Archean]

The recommended power supply for a 9800GT is 400W with 26A (combined) on the +12V rails.

Manufacturers of cheap/generic PSUs often exaggerate the wattage of their products. Looking carefully at the specifications on the label (like amps on the +12V rail) is often a much better indication of the capabilities of a power supply (e.g. if you come across a 500 watt power supply that only has 18A on a single +12V rail, then you know it's problem, it's probably more like a 300 watt power supply.)

 

[deadeye93]

Well it has 2 20A rails, but i think currently only one is plugged in (i didnt assemble this pc)
when i disassembled and reassembled it i didnt see another place to plug the 2nd rail..

 

[Archean]

If you have plugged in that six pin connector and if the power supply has no issues you should be alright. To clarify things out have you checked system logs there may be a clue to your problem in them?