I think i can offer some insight to the issue. I am using 7870 extreme versioon and I installed the sapphire Trixx tools. My card normally run in 925MHZ, however, whenever I teleport, durign trh loasing screen the speed will drop to 501mhz and it will go back to 925 after teleport is finish. However, sometime it will not and the game crawl at 501 till it crash or sometime it recover. And with hunt going it, it crash even more often.