Hi everybody, I bought SAPPHIRE Radeon NITRO R9 380 4G GDDR5 OC DUAL-X model today to upgrade my Mac Pro 5,1 (mid-2010). I successfully replaced old 5770 using additional 6-pin power cable from broken GT8800 I used before. However when I powered up my Mac Pro, fan of R9 380 does not move at all, and I cannot see anything but black screen after I hear booting sound and HDD sounds usually I hear during booting process. I checked power cables and ports by testing 5770 with each one, and both were successful. I tried to change PCIe slot to second one, result was same. I also tried to change BIOS setting dip switch, but nothing changed. Difference between my graphic card and the card mentioned in this forum is that SKU number. Everyone is talking about 11242-13-20G, but mine is 11242-13-42G. I live in South Korea and this model is unique one for 4G GDDR5 R9 380 that I can buy here. I cannot find any other model from sapphiretech.com with same family name and VRAM capacity. What can I try more to fix this issue?