computer hangs on a black screen

[zenyora]

MrCoffee: thanks for this man i am going to try them now but let me just give you an update as you might help me narrow it down...
first here is a video of what exactly happens
YouTube - GPU CRASH
as you can see it just goes black, sometimes red , sometimes its a white and black striped screen(ill try a take a pic off it when it happens) .
until today i thought it might be the graphic card, so i called xfx and was going to rma so i bought a new card(same one) put it in and started testing with crysis, and same thing happened but not as fast .
so i thought it might be that the pci slot is damaged so i called gigabyte tech support for an rma and while i was talking to them the guy mentioned that the other slot run also on 16x and i should try that , so i unpluged the new card from the first slot and pluged it into the second one and ran crysis and just around 15 min into game play same thing(white and black striped screen ) .
could it be that both slots are damaged?or even both crads are damaged?

as far as the psu goes i have a 550 (antec true power 2.0), with 1x 4 pin pluged in the bored for the cpu power instead of the 6 . which as far as i know should be fine , i even tested with prime just o make sure and everything was fine .

i did all this on a fresh install of windows with the latest drivers.

now my next step i guess to make sure its not the psu , what i should be looking for and how can i test that ? or could it be something totally different?

 

[zenyora]

here is a screen of what my screen would look like
http://img411.imageshack.us/img411/892/imagem000.jpg

 

[MrCoffee]

as far as the psu goes i have a 550 (antec true power 2.0), with 1x 4 pin pluged in the bored for the cpu power instead of the 6 . which as far as i know should be fine , i even tested with prime just o make sure and everything was fine .

The true power 2.0 550? I had that in my last computer its an alright PSU (for its day), I never had any problems with it. But i'm a bit worried about what you're saying about the motherboard power as the symptoms you're getting seem a bit like a power issue.
As I understand it there is normally either 4 or 8 pins for extra mobo power (12v) under the ATX 2 specification - under the earlier ATX there was a 6 pin connector (5v) but it was a single row of pins and I'm pretty sure that won't be on your motherboard as its really old.
Prime95 won't max the power consumption of your board by the way, the graphics card will pull power from the PCIE slot and it could be that that is tipping you over the edge - its a theory anyway.


... I just looked up the manual for your mobo and it is an 8 pin 12v connector

http://europe.giga-byte.com/FileList/Manual/motherboard_manual_ga-ep45-ud3p_e.pdf

I think maybe we are closing in on the problem here... Though I am wondering why your mobo needs the 2x4 connector, i've only seen that before on 2 way systems. I would of thought a single 4 pin connector would of been alright but then why does it have 2x4 ?

Excerpt from manual (i'm sure they use babel fish to write these things):

ATX_12V_2X4/ATX (2x4 12V Power Connector and 2x12 Main Power Connector)
With the use of the power connector, the power supply can supply enough stable power to all the
components on the motherboard. Before connecting the power connector, first make sure the
power supply is turned off and all devices are properly installed. The power connector possesses
a foolproof design. Connect the power supply cable to the power connector in the correct orientation.
The 12V power connector mainly supplies power to the CPU. If the 12V power connector is not
connected, the computer will not start.
ATX
• Use of a power supply providing a 2x4 12V power connector is recommended by the
CPU manufacturer when using an Intel Extreme Edition CPU (130W).
• To meet expansion requirements, it is recommended that a power supply that can withstand
high power consumption be used (500W or greater). If a power supply is used that does not
provide the required power, the result can lead to an unstable or unbootable system.
• The ATX_12V_2X4 power connector is compatible with power supplies with 2x2 12V power
connector. When using a power supply providing a 2x4 12V and power connector, remove the
protective covers from the 12V power connector and the main power connector on the motherboard.
Do not insert the power supply cables into pins under the protective covers when using a power
supply providing a 2x2 12V power connector.


The max TDP of your processor is apparently 95 W so I guess it should be ok... I'm suspicious though.

You know I think you can get a 4 pin molex converter cable to plug in beside the other one... It would at least help rule this out as the problem.

This sort of thing:

PI Manufacturing Corp - Motherboard 12V P4 4-pin to Molex 4-pin power Adapter Cable, 12in

The other thing is, what pins do you have your 4 pin connector plugged into, the manual seems to suggest that if you have only 1 x 4 pin connector that it should be in pins 3-4 7-8 (the side closest to the CPU).

 

[zenyora]

thanks for the help ..well i just got back from best buy , i bought the thermaltake black widow 850W psu , and still same issue so iam not sure if that rules out the psu issue or not .
but i also found this
AMD Game Forums - Radeon HD4850 Crash Vertical Lines!

this is really driving me crazy , because even with a new psu and a new card it is still doing the same thing .

 

[MrCoffee]

Hmm, I was afraid of that. Well ruling out the PSU pretty much leaves the motherboard doesn't it, I don't know what the odds are on both graphics cards being duff in exactly the same way. Do you have an old PCIE card lying around somewhere you could try?

 

[zenyora]

on the OC forum a group of people did a return all the same time because they all had the same problem with the HD4850 xxxx edition

Is there a compatibilty problem with the ATI 4850 and Furmark? - Overclockers UK Forums

so in short the XFX HD 4850 xxxx edition is defective..i just requested a refund for the new card and going to send it back tomorrow.which leave me stuck with the old one. which iam going to call xfx and see what they say . i hope they either give me a different card or refund me my money because replacing it with the same card like a normal RMA isn't going to do anything and i refuse to be stuck with something that doesn't work..