Hi. I picked up a 4,1 used and I noticed something was loose inside. The seller tells me he replaced the Northbridge mount from plastic to a metal screw. What are the acceptable temperatures at idle and at load? I'm thinking I would run geekbench burn in test. Is this acceptable? Will I see problems down the road? Is there a heatsink on the bottom of the CPU tray? I did a quick search last night and there are a few threads of these little black pieces breaking off and difficulty of finding replacement units. Do you think something had to be drilled out? What prompted me to contact seller is the fact I heard something loose. I'm afraid the little spring is loose somewhere waiting for a short. The computer looks very good, it does have a slight bend to one of the handles, but other than that is nice. What's good is it's dual 2.66 which is a little boost from the base dual 2.66 I looked now on ebay and do not see many 8 core 4,1 at all.