Thanks all for the thoughts. Air flow was not the problem. The computer does not look all that nice, but there is a decent fan in the front behind that plastic bracket at the lower right of the picture. I did remove a couple of rather minor dust cakes inside the card, but there really was not much to speak of. I don’t think it was restricting air.

I did reapply what little thermal grease I had on hand though. I only had enough for a super thin layer all around. I reused the the thermal pads. Either the old grease dried out (probably) or just the act of disassembling and reassembling the card allowed for better thermal contact. I am going to disassemble and do it again the right way once I get a new tube of paste and some padding.

It is running much quieter now.