Just finished this refurb…. fantastic site and great guide.
The GPU was overheating, and initially, I used SMFan to increase minimum fan speeds and disabled the GPU by following this video
but obviously this limited performance, so I thought , maybe refreshing the thermal paste was help and it has - I decided to do the CPU and the GPU at the same time and the only issue was the antenna terminals broke on the Bluetooth board as I remove the cable - being a bit heavy handed.
A Bluetooth dongle later and this is all fine, the system still runs a little hot, but that’s to be expected and for a 13 year old Mac, its pretty good.
Thanks Folks - really wonderful.
Finally got round to looking at my late 2006 iMac, and GPU overheating is the major problem now.
A temporary fix is to disable the GPU, but obviously with all video processing via the CPU, the performance is poor.
Next step - see above….got some new thermal paste - maybe it will work.
I’ll let you know