I had the same problem with asus gtx 980 platinum matrix.
1 GPU, the panel came with a yellowish tint, and a GPU using 99%, the LED was yellow. A maximum load gets 60 degrees.
I made an RMA and sent me another graph with the LED without that has yellowish.
2nd GPU, GPU usage with 99%, the LED is yellow and it also has a problem with the thermal paste to the maximum load temperature reaches 70 degrees in less than 10 minutes in the game, but since I can not open because I lose the warranty, I have to redo another RMA.
Wear one month with these problems, and two weeks waiting send me the 3rd GPU and unable to use the computer.
I think these graphs are coming out with quite failures factory for what they cost and be a top-end product.
I'm reading a while ago, and I'm having the same problems as you.
In this thread you can see photos and my problems with these two GPUs.
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https://rog.asus.com/forum/showthread.php?56005-Donde-comprar-GTX-980-Matrix-Platinum/page9I hope to get lucky with the 3rd graph.
I am forgiven for writing Spanish and I use google translator.