R31 cpu speed throttling down.

[calais86]

Hi everyone. Wanted to see if anyone on the forum has had this problem or can recommend some solutions. I recently picked up a used R31, model number 2656-L2U at a good price. (It's a celeron 1.2GHz system.)

I noticed that the system seemed to slow down after some mild usage. I ran CPU-Z to monitor the processor frequency and noted that my 1.2GHz machine was running at 147MHz. I thought it might be a fluke so I shut it off and came back to it. To make a long story short, everytime I put the machine under heavy load, it starts to overheat. The funny thing is, I will hear the fan come on full speed for about 15 seconds, then the CPU drops to ~150MHz, never speeds up to 1.2GHz, even under 1% load, and the fan slows down and never fires up full speed again.

Has anyone else had this? Any good programs out there that might give me an idea as to what is happening? I would think the fan is bad, but when it does come on, it sounds fine. I guess the "deal" I got wasn't a deal after all.

Any advice?

--James

[Thane_Bitter]

Have you considered using a temp/freq monitoring tool called "mobmeter" or mobile meter? Here's a link to the developers page http://www.geocities.co.jp/SiliconValley-Oakland/8259/ you can download it from there. Not only does the tool give you CPU frequency but temperature information as well.
I have noticed with my R31 the fan has about 4 or 5 distinct speeds it operates at, though the maximum speed only seems to occur at start-up or during a BIOS upgrade (never for regular cooling). Most of the time the fan is either off or at the first or second speed range depending on what I am doing. I have managed to force the CPU to drop frequency because of overheating but I had to block the air intake, exhaust and run a CPU intensive program to do it (happened around 97 to 98 degrees C)
If you have not done so already, download the power management software from IBM/Lenovo and I believe that there is a patch for the CPU as well, look for that as well. Hopefully that will solve the issue.

Thane

[calais86]

OK, I managed to slow my problem. Thought I would share it with the forum.


I had this suspicion that the problem was with the heat sink not properly sitting on the CPU. So (being an Electrical Engineer by education) I decided to pull my R31 apart. I do so love IBM…. their documentation is really second to none! (I was very depressed when the unit got sold to Lenovo.) I downloaded the field replacement manual, and got to work. I took the heat sink off the CPU, put on a bit of thermal paste, and put my baby back together. Well, after about two hours of work, I got my R31 running great! Ran three hours of Prime95 torture test with mobile meter on, the CPU speed dropped to 933 MHz briefly only once and then popped back up to 1.2GHz.

Thanks to all who took a look.

--James

[Thane_Bitter]

Glad to hear that your ThinkPad is up an running again.

[calais86]

Me too! Thank you for the initial suggestions.