Mysterious CPU Performance Loss Solved
I just started to notice that the CPU in my main desktop machine was grossly underperforming, despite BIOS tools telling me it was running at nominal speed. It’s a (now old) Pentium 4 3.0 GHz HT single core which has been fine for what I need up to now, but lately I’ve been getting massive frame-rate problems with MS Flight Sim 9.
I should get around 20 FPS (I’m using some really detailed sceneries and aircraft) but it was topping out (!) at around 4. This is unplayable.
In the BIOS I found an option entitled “CPU Internal Temperature Control”, which apparently means that if the chip gets hot, it internally idles to prevent overheating. This occurs while the FSB and the internal clock gen operate at the same frequency (according to Gabriel Topola’s excellent SIW – System Information for Windows.)
I turned that off and started Flight Sim. Temperature shot up to 98°C (the last time I was able to check it) then the machine shut down – it didn’t halt, or hang, it turned off – completely.
Spring cleaning time. I took the CPU fan off, took the CPU out of its ZIF socket and cleaned all the thermal paste off both parts. The paste had totally broken down. I blew out the CPU fan (outside) and a very large quantity of dust came out. New paste, replace the fan assembly and voila – 20 FPS and the temp tops out at 55°C.
