MacPro 5,1 Heatsinks question

Thanks for the response.

I think the broken plastic springs is unlikely.

I can't figure out how to edit my post above on this new Apple community, but I meant to say (above) that I had the processor board replaced less than a year ago. The tech who repaired my Mac used to work for one of the now out of business online Mac supply shops (I think it was Mac Warehouse), and was offered dirt cheap, brand new parts. He bought pallets of hardware. He happened to have a dual processor board, new in box, never used, sitting in his back room for close to 10 years. The board had the Northbridge heatsink attached. It never cycled on, so wear from heat would not be a factor. The board was still in the box, in the packaging, wrapped in plastic. I used the box and the packing/wrapping to sell my old board with bent pins (buyer was aware of the pins).

Will do, and will report back.

Incidentally, does anyone know the difference between the 604-1164 and 604-1165 heatsinks?

So here's the saga of what happened next.

I did the wiggle test. Northbridge heatsink was on tight. Clips were fine.

I decided to take it (all) apart and check the thermal paste on the Tdiode. I took off both heatsinks, took out the processors, (took out the RAM) and unscrewed the board from the tray to release the clips. I removed the NB heatsink, and the minimal paste on the Tdiode was chalky and dry. I scrapped that off, cleaned the diode and the heatsink, then reapplied Thermalright TF8 on the diode. Reattached the NB heatsink, and focused on the CPU A and CPU B.

I cleaned off the processor chips and the heatsinks, then…no more thermal paste! Even though the plunger was still sticking out about half an inch! (I don't think I'll buy Thermalright again because of this BS.) I was frantic. All the Staples and Office Depot and OfficeMax have closed down in my area. The only computer repair shop in my area wasn't opening for 3 hours. While I was weighing driving 20 minutes to the nearest BestBuy to buy Corsair Paste, I noticed that a pin on CPU socket A was bent. My heart sank. I had to replace the board less than a year ago because of bent pins. Then I noticed a second bent pin... then a third. I was gonna burst into tears.

I thought, "What do I have to lose now?"; grabbed my wife's sewing kit, and pulled out the thinnest sewing needle. I put on my bifocals (that I never wear), went extreme close-up on my phone's camera, and gently and painstakingly tried to bend back the pins. By the time I was done, the computer repair shop was open.

All they had was some cheap Halnziye HY710, but I was desperate. This stuff only has a 3.17 w/mK(!) as opposed to TF8's 13.7 w/mK. Anyway, I applied it to the processors, sending up prayers that my board isn't toast.

It booted! I'm currently using it to post.

The ironic thing is that the temp on the NB didn't really drop much (if any). I'm not sure if it's because the paste needs time to cure. TF8 gets mixed reviews.

I do know, that as much as I hate to go through this again, I'm going to order the Arctic Silver paste and remove the crappy Halnziye paste from CPU A and B.

Fingers firmly crossed.