Quote Originally Posted by chispy View Post
Thank you for trying to help me Ace123 , apretiate it.

Finally I have an answer after many many long hours testing and re-testing my 290x with every driver available and 3 different OS w7 installations , card has not been volt moded yet. The problem is related to the video card throttling down during heaven , it does it 1340/1677Mhz stable and pass heaven DX11 extreme on water full cover EK H2O block , but the card starts throttling at test #11 once it gets warmed up the clocks goes up and down as well as the FPS ,performance take a nose dive due to the v.core set at 1.43v real via DMM reading , water cannot handle that much heat , LN2 required for stability. Big Thank You to Crustytheclown for all the help. I guess finally I found a Golden card , I am happy as a dog with 2 tails . next will be full volt mods and LN2 to make it scream.

Here is a short video I made of a complete run of heaven at 1340/1677Mhz on ambient temps H2O, I selected and only showed the last 2 test #25 and #26 because heaven last almost 5 minutes to run lol , the fps starts very strong from test 1 all the way until test 10 fps are 186 max , average 182 ,then it takes a big performance hit after test 11 once the card is warm game over :/. darn it took my 6 cards to find a golden one. watch the short video and the FPS. Check it out to see what I am talking about. id you are having the same problems as I did , there is your answer.

http://youtu.be/GQoXT319nvs
I watched your video and I face with the same problem : by using Displayport, the display becomes black randomly when I apply about 1.35 V with ASUS GPU Tweak or +160mV with Sapphire Trixx. On the other hand, with DVI, instead of black screens, the display flickers, becomes blurred randomly. I must diconnect the DVI cable to have a crisp image.

I am watercooled : the GPU does not exceed 45?C and the VRM1, 60?C. Your conclusion is the heat too high for watercooling.

I am not sure that it is the cause when I see our temperatures. Furtermore, I thought that the cause might be the RAM overheating but even at the beginning of benchs, when the RAM is cold, the problem appears. According to me, the causes may be either the VRM circuitry, not stable enough for high voltages. Or the GPU which does not like too high voltages. I tested on around 7 290/290X cards and every card encounters the same problem.