Hi, I bought 2 X5690 on ebay, the seller ensured me they were 100% working. (seller is feedback is 100% with about 800 sales) I delidded them with the vice method (not testing them before I did (silly me)) I found the delidding whent very easy, the removel of the solder was a bit nerve wracking, though I think I did well. These were then placed in my new (old) mac pro 4,1 (with 5,1 update) dual processor tray replacing the two E5520. But when I switched on the Mac, there was no bootscreen and no chimes, only 'fainth' fans spinning. I removed them, installed back the E5520 and the Mac booted perfect, did the switch again, only one on CPU A now and still no boot, switched the other X5690 and the same result. did this several times with different tightings on the heatsink, with no result. After few athemts I saw that 3 pins where bent on the socket, they also looked like they got hot, the color was off. I bend them back in place with a microscope, unfurtanatly 2 broke at the top, I got them straight up, so maybe they still make a connection. I tried it with replacing back the E5520 and the Mac worked back again. So, did I brake the X5690 cpu's? Is the problem in the placing? (I hope it is the latter) I tried also one X5690 in a single tray (from a 4,1 updated to 5,1), but this was not possible because the heatsink did not touch the CPU. Thanks!