I'd like to report some tests with T61 and fanless operation. It's a 15.4" inch model, with T7100 cpu, 2 GB RAM, Hitachi 7200 rpm 100 GB hard drive and Intel x3100 graphics.

When running at 800mhz and fan stopped with tpfancontrol, cpu temperature is around 60 celsius in light use, and tops out at 80-85 celsius degrees while loaded 100% with Intel TAT or Orthos for several hours (no throttling). Other temperatures remain below 60.

While 80-85 celsius might sound high for CPU temperature, it actually runs just as hot with fan and 1.8ghz speed under load, and many notebooks can reach 90-95 celsius degree cpu temperatures under load, and 100+ degree GPU temperatures.

However the surface near the heatsink gets hotter than with fan, so in fanless mode it's not comfortable to use in lap. However for desktop use it's no problem at all.

If you're scared of overheating, you can set the fan to start at 85 degrees with tpfancontrol and enjoy fanless operation all the time with overheat protection.

did you try some undervolting with rmclock?
i just use that and in lowest mhz the cpu allows, and lowest voltage the mobo allows the fan basicly never turns on.

Haven't tried that yet, it was running at 0.85v @ 800mhz. Propably could go a little lower.

Hm, I might try some underclocking with my R61. Thanks for the info, OP.

I tried this on a T2010 (1.2 duo, x3100) and running RMclock taxed the system so much that temps went up, and the fan on much faster than with it disabled.

Paha, I have an R61 and I've noticed that unless I'm really taxing the system I hear my hard drive (100GB Seagate Momentus 7200.1) over the system fan. Sounds like pieces of paper rubbing together. Are your experiences similar? How loud is your hard drive? Perhaps I should think about switching mine out, as it's my main source of noise (the fan seems quiet enough for me).

I heavily considering getting an R61 with a t8300. Should I go for the t8100 which is 40 bucks cheaper? It's also clocked 300mhz slower, but that might reduce heat and noise.

Can you set 0.85v in BIOS, or is that running RMClock?

0.85v and 800mhz was set with just thinkpad power manager (cpu speed - lowest).

Wow, this sounds like quite a breakthrough.

Others trying this sort of thing have often reported the dreaded Intel CPU low voltage whine? Is there any high pitched noise if you put your ear down near the keyboard?

Haven't heard any whine, though i mostly use it work where ambient noise level is quite high. I might try again at home.

And about the fan - i used tpfancontrol to raise the fan startup temperature to 85 C.

I've been running it with fan and full cpu speed most of the time though, because at work ambient noise level drowns the fan noise completely.

Ressurecting this old thread..

Aside from the fan and heat - how do you guys like your T61 systems?
im looking at a new laptop here real soon and this one is at the top of my shortlist.
how is performance? battery life? reliability?

Idk, if I were you, I'd consider the T400 / T500. Just released, latest chipset saves power and heat. And, there was a 25-30% off deal that made the prices somewhat reasonable...

The R61 is by far the best laptop i have used, the R61 should be better, and the new T400/T500 look even better. LED backlights, 3dB quiter than previous Ts..(from lenovo site)

As for realiaility, mine has dropped to the floor several times and still works like a champ. I have also punched the keyboard rather hard. I've replaced the HDD once, but that seems to happen on all my laptops.. As for battery life, i get about 8 hours with the 6-cell + 3cell ultrabay battery, can't really remember what it was like with the stock battery. Basically these things just work.

This post was written very, very tired so i take no responsibility for anything i've said..

Yep the new T-series seems to have lower fan speeds, level 1 is down to 1800 rpm from 2800, which already was tolerable on T61.

And tpfancontrol works.

http://forum.notebookreview.com/showpost.php?p=3792202&postcount=27

Despite my tests with fanless T61, I wouldn't run it fanless, as even the temperatures are below CPU throttling limit, other components run hotter too.

Thanks for the tips. I'll checkout the T400/500 as well.

im not after any specific model - i just want something that will run and run and run.
I have an old A31 from 2002 (see sig) that still works fine. the only thing is its OLD and hard to find software for anymore. im after something that will last another 6 years.

Well, I looked at T400/T500 & they seem interesting, but they are quite expensive here in Slovenia!
(& I'm not even sure if they are the same model/as environmentally friendly as the main website says..)

Just curious, but it looks like all the fan control for the T61 is for linux. Is there any Windows software that does fan control on the T61? It doesn't look like speedfan is able to do so on mine.

In term of battery life, I get around 3.5 hours out of my R61e 7650 (T8100 2.1Ghz). In windows, the fan is controlled indirectly by selecting the power profile in the Think vantage power settings.

I'm late but, for the record, one can use TPFanControl but you can't make it run slower than 2900 RPM except by turning it off.