Just done a thorough test for WX7100. It seems that it's gpu frequency will drastically decrease during high load, sometimes I can't even get 600MHz. This caused some sudden lags in games.
It turned out to be an aggressive temp throttle, which happens around 92-93℃. I disassemblied the top cover of the heatsink, only to find that the density of fins are severely lower than that of the old Firepro W7100. That's why W7100 only got 86℃ at full load when WX7100 is up to 93-94 and have a much louder noise. This harms both the user experience and performace, and possibly, stability.
So can AMD have a higher standard in these matters? I don't think a few fins can really cost more, since this card is already using top-level mosfets and caps. Look at quadro P4000, it really has a nice dense fin block inside.