EK-FC280 GTX owners with high GPU temperatures

[cx-ray]

It's a little bit difficult to tell from the SLI image by you a few posts back, but it looks like you're using the two center screws above and below the GPU. Due to risk of warping EK told people not to use those screws in the older blocks. In later block revisions EK also completely left out the top and bottom center screws holes around the GPU

...maybe worth a try if you haven't already.