T20 Brain Surgery - 650 > 850 CPU

[verktyg]

I just swapped out the PIII 650 in my T20 for a PIII 850 CPU. I replaced the main board last month so changing the fan & CPU was a piece of cake.

This is a low mileage TP and it was running great after the new mainboard and BIOS update. I installed WinXP for better WiFi and set it up to dual boot with Win98SE. I also increased the memory from 256 to 512MB for XP.

I'm a little disappointed at the performance difference between the 650 and 850 CPUs. Over the years I've upgraded the CPUs in a number of desktops from 500 to 750 and eventually 100MHz. I was expecting to see a bigger boost in performance.

Last year I installed a Hitachi 60g 7200 RPM HDD, that was a major performance improvement. The additional 256MB of memory helped load programs a little faster with the original PIII 650.

The 850 CPU boots about 5 seconds faster in both 98 and XP. The 7200 RPM cut boot time in half with Win98SE and the old 650 CPU versus the original 4200 RPM HDD.

I picked a PIII 850 instead of a faster 900 or 1000 MHz CPUs because the faster PIIIs use 1.7/1.35V whereas the 850 and lower Mobile PIIIs run at 1.6/1.35V which the mainboard was designed to handle. Also, I used one of the older 04P3295 heatsink/fans that came with the 850 T22s.

The newer, high capacity fans for the PIII 900 and 1000 CPUs sell for $45-$75 on the web. I bought the CPU and fan for about $12 each plus shipping. I didn't want to spend too much money on a TP only worth about $3-400 and wont be used very much.

I ran MobileMeter in XP with the PIII 650 and 850 CPUs at 20°C (68°F).

PIII 650
Idle 34°C
Running SpyBot 74°C (fan did not run)

PIII 850
Idle 46°C
Running SpyBot 77°C (fan started at 73° and stopped at about 47°)

Note: Fan ran a lot more in Win98SE that XP with both CPUs but I didn't have a way to measure the temperature in 98. I'd recommend anyone with a T20 or T21 to install one of these 04P3295 heatsink/fans. they run a lot less than the older fans. They're cheap on eBay.

[JonathanW]

Thanks for the info Chas. Having put a 1GHz into my T21 (now with a T22 system board!) I was interested in your findings.

My system runs at ~47C idle. Under constant load it reached 96C(!) but continued to run ok. As the TP is used for background processing this will never be a problem day to day but I would like the thing to run a little cooler in general.

I have long since been confused about the T20/21/22 fan situation believing there to be a 'better' fan in the T22. It is this part I think I need now I am running at 1GHz.

Are you saying that the fan you are using is the lesser T20/21 part - I have just checked the part number of my fan and it is indeed the 04P3295/04P3448 which I thought came as standard. I am just a little (more) confused as you say your fan runs less than the 'older' style and yet from what I can fathom, the 04P3295 IS the older style?

<later>

Ah, ok, sorry - just found another thread where you clearly state the T22 fan assembly is part nos. 08K7268 or 26P9317!!!

Any idea where this can be sourced? Absolutely no sign of them on Ebay!!

Jonathan

[verktyg]

Thanks for the info Chas. Having put a 1GHz into my T21 (now with a T22 system board!) I was interested in your findings.

I have long since been confused about the T20/21/22 fan situation believing there to be a 'better' fan in the T22. It is this part I think I need now I am running at 1GHz.

Are you saying that the fan you are using is the lesser T20/21 part - I have just checked the part number of my fan and it is indeed the 04P3295/04P3448 which I thought came as standard. I am just a little (more) confused as you say your fan runs less than the 'older' style and yet from what I can fathom, the 04P3295 IS the older style?

Jonathan

Sorry for the lack of clarity. The 04P3295/04P3448 fan seems to have been used in the later PIII 800 & 850 T21s and early PIII 850 T22s. It has more capacity than the original T20 fan designed for the 650 & 700MHz CPUs. In my T20, it seems to run less than the original fan did with the 650 CPU.

I chose this model because the price was right plus it has a large heat tube that keeps the heat away from the keyboard. If it didn't work, I'd get one of the more expensive fans.

Over the years IBM has used a number of different fans in the T2x series TPs. To add to the confusion, IBM has 2 different "part" numbers on most of their parts. There's an ASM number and an FRU (Field Replacement Unit) number.

In your situation since you have a T22 mainboard and 1G CPU, you might want to get one of the 26P9317 fans used on the later model T22s.

Check out the link in this message in the T forum:

http://forum.thinkpads.com/viewtopic.ph ... highlight=

Hope this helps.

[wogeboy]

Update:
OK, installed the new T22 fan/heatsink and popped in the 1.0ghz cpu (SL53S).
I used silver thermal compound (just to be sure)

I then changed my maximizer settings (adaptive etc..)


I did a test at full speed (995mhz) :
Normal usage (no heavy load) temp averaged 46-52C
At full load got up to 83C

Fan seems to run well, actually runs less than the T21 did...not sure why.

During adaptive mode, it generally was in the 48-55C range...not too bad I think