Hey guys I have researched the issue a bit and found that apparently the EK FC GPU waterblock can cause the HD4870 X2 to not start up...something about the M3 x 6mm screws needing nonmetallic washers to avoid some sort of short circuit. The problem is I used washers as instructed and still got nothing. Has anybody else had this problem mounting an EK FC to an HD4870 X2? I've tried everything I can think of and before I return the lovely blocks I thought I would see what others have done to work around this. Thanks. http://www.hardforum.com/showthread.php?t=1343401 Here's a thread with that issue http://www.overclock.net/ati/388361-solved-4870-x2-no-longer-functions.html And yet another thread this one by an experienced LC modder with the same issue http://www.ekwaterblocks.com/download/EK-FC4870X2_installation.pdf The EK PDF that mentions using the washers http://ekwaterblocks.com/shop/product_info.php?cPath=21_31_42&products_id=303 And a mention of the issue on the EK site. It's driving me mad since this is for a client and I am supposed to know what I am doing I have mounted nearly identical blocks on my HD3870 X2s without issue...so I know the routine..or thought I did. What amazes me is that EK would even have a problem like this with their gear. Thanks in advance.