Undervolt your nVidia NVS 140M with modified BIOS (Tested on T61) [ Edited ]

[carpediem90]

Hello lads (and ladies)!

I want to share something very interesting, something that we waited for a long time. Some guys made modifications to BIOS on T61 and they manage to undervolt the GPU, without any soldering.

I'm running BIOS mod for 0.95V (on my T61) on GPU (constant, without switching as on default values form 1.15-1.2V) and it works flawlessly. On the link below, there is a tested BIOS list in table with functions description.

BIOS version is 2.27 (EC 1.08), with white list and SATA 2 enabled and this is the base for every modded BIOS from there. There's also some other modifications, like updated microcodes list, so you can actually run newer CPUs on your T61.

Before you decide to flash your BIOS with this modified version, make sure that you already have EC version 1.08! THIS IS SUPPOSED TO RUN ON T61 and I can't be sure if this can run on any other model.

And of course, YOU'RE DOING THIS AT YOUR OWN RISK!

German link, so you can translate the page with Google translate: Link

Compressed file contains only BIOS, without any flash tool. You can find the flash tool in first post and I'm not going to link it here, because I want to make sure that you actually read the text from there first.

The procedure is as usual. You need to make bootable USB drive (with DOS), copy the BIOS file (you have to rename BIOS file to BIOS.ROM, because .bat file contains that BIOS name) to USB drive + flash tool and .bat file. After you boot from USB, just run that .bat file and wait to finish.  

Good luck and share your experience!

EDIT: here is the screenshot that shows a new voltage on GPU on my T61 (as I said, I picked BIOS for 0.95V).

[carpediem90]

I'm testing this for 2 days and I can say that temperatures are excellent and I got a much better battery life.

[carpediem90]

I can't believe that no one tried this.

Lower voltage also means lower current - in total lower temperature for your nVidia GPU. This is something that could prolong your possibly faulty nVidia GPU chip.

It's working on my system for 2+ months and it's great.

[ssvb]

Sounds very tempting, but what are the risks? For example, will it be possible to reflash the bios back to a working state if the voltage turns out to be too low to operate the GPU safely?

Additionally, is the location and data format of the voltage tables inside of the firmware properly documented somewhere? How did these guys come up with a working bios modification? Are they using some secret insider information? Or have they reverse engineered the bios?

[carpediem90]

Every BIOS was tested before launch, so there is actually no risk. But however, some users were complaining about version with 0.9V, because every chip is different. That's why Lenovo left a lot of headroom in voltage. As you already saw, some users overclocked the chip over 50%. However, I think that GPU voltage on Lenovo is slightly higher than on other brands.

As I said, I'm running @0.95V and it runs perfect.

BTW, I don't know how these guys came up with voltage tables in BIOS, but It's more or less similar to any other Phoenix BIOS.

[ran23]

I tried one of the other programs to undervolt, but it wouldnot open.  I asked but noone could tell me if it would work on my 6460-DWU.    

[carpediem90]

I'm not sure if you understood this right. This is the BIOS mod, not a program. If you flash with one of these BIOSes, you'll get permanent settings for your GPU (undervolted oout of the box).

Any yes, this BIOS mod will work on your T61.

BTW, I'm using the same BIOS from the first post for 6 months and it's absoulutely perfect. I also bought a OEM 9 cell battery with 8800mAh and I'm getting about 5 hours of moderate use. 

You get cooler laptop (lower GPU temperatures) and better battery autonomy.

[zsoltiabeka]

This is really cool and I don't undertand why it is not used by more T61 users.
I just updated the BIOS on my 14" nVidia 140M T61 using the link in the first post and I am pleased with the results although I only tested it for a few hours.
The flashing went without issues but the 0.95V mod did not do the job. Windows hang at the start of the animation(I am using Win7 Ultimate 64 bit). I guess 0.95V was just not enough for my chip.
I re-flashed with the 1.00V mod (no overclocking) and the machine booted just fine.
My idle temp is better: 48 C CPU and 50 GPU (before it idled at 56-60 CPU 60-62 GPU) according to TPFC and battery use is better 4:00h vs 3:20.
I did not notice any performance issuens but this will take time, same goes for reliability. I do not use the T61 for GPU demanding stuff so in theory this is perfect for streching the life of the problematic GPU(mine is 2008 June...).
I will be back with updates in a while, hope there are some T61 users willing to try this out and share the experience.