Initial reports indicated the GeForce GTX 1080 Founders Edition has significant thermal throttling issues. Despite NVIDIA charging $100 for the reference cooling design, the Founders Edition suffers from poor cooling that results in a lot of throttling after just a few minutes of gaming. On average, the card runs around the officially stated boost clock but all the frequency spikes cause issues like micro-stuttering and result in a poorer game experience.
Dutch tech site Hardware.info tested the MSI GTX 1080 GAMING X and found this card to be significantly better than the Founders Edition. The MSI GTX 1080 GAMING X runs at a very constant 1910MHz and has a GPU temperature that doesn't exceed 70°C.
Meanwhile, MSI GTX 1080 GAMING X generates almost a straight line for GPU frequency (~1910 MHz), with no spikes and rather constant sub-70 C temperature. This should mean that the gaming experience will be much better, and card should theoretically generate better results in most tests. Also according to H.I. this is also the best custom design they so far tested.
One negative remains though, it seems the GTX 1080 is a poor overclocker. Hardware.info could not push the GP104 GPU above 2062MHz, which is a lot lower than the 2114MHz promised by NVIDIA.