Thinkpads Forum

Hey All,

just a quick news in case you missed it

there is a new modified BIOS for the T61 that undervolts the Nvidia GPU

there are actually various BIOS files available, each of them with their own characteristics, allowing to undervolt the NVS140M GPU to 1.05V, 1.0V, 0.95V, 0.9V. some of those BIOS files also enables ASPM, quadcore CPU APIC support, and slight overclock.

I am using the "plain" 0.9V BIOS (no quadcore APIC, no ASPM) and it works perfectly on my T61 with NVS140M. The voltage is reported correctly by all the software tools, it is super-stable, and the temperature is wayyyy down! (around 10C less than before!)

More info from here:
OBVIOUSLY, YOU DO EVERYTHING AT YOUR RISK! PLAYNG WITH BIOS CAN BRICK YOUR LAPTOP : )
https://forums.lenovo.com/t5/T61-and-pr ... -p/1721929

What is even better is that the bios supports 1066MHz CPUs with a simple mod

That is awesome. If your GPU can run at .9 volts, its power consumption is reduced by 40-45%!!!

will this work with the t61p?

f33lmywrath wrote:will this work with the t61p?

yes but you'll probably get down to 1.00V at most

I eventually decided to apply one of these modded BIOSes to my T61p (I was hesitant — afraid to brick my board…).

I made several tests with different voltages and I am now happily running my QuadroFX 570m at 900 mV. It is not stable at the stock frequency under high load (it seemed to be stable at 950 mV) but since I never use my GPU at its full power, it is not a problem for me. I can confirm SLIC 2.1 is present, that my Penryn T9300 still works ; the only thing is that Dual IDA doesn't seem to work anymore, but that's not a big deal.

The temperature and power consumption difference (compared to 1150 mV) is obvious ! Hope it will help my GPU to last longer…

If it can be useful to anyone, here are my different clock settings (in the form Core freq, Memory freq and Shader freq), all at 900 mV :
— For normal use : 169 MHz, 100 MHz, 338 MHz (I used to set it to 80 MHz, 80 MHz, 160 MHz but with these settings I had to restart the video driver after sleep/resume, so it was kind of annoying) ;
— For most 3D apps : 330 MHz, 660 MHz, 702 MHz ;
— For intensive 3D apps or CUDA computation : 430 MHz, 680 MHz, 920 MHz (seems to be stable ; not too far from the stock frequencies, i.e. 475 MHz, 702 MHz, 950 MHz).

Passing all tests does not implies fully stable.
I tried the 1.05V BIOS a few months ago, under windows 7 everything seemed to work fine. It even passed the furmark.
However under windows XP the screen freezes quite often. And a few weeks later my beloved T61p passed away
FYI, I could overclock my FX570m to 500+mhz before, 3dmark 03 scores abt 12000+
P.S. Is there a way to force install 8600m gt driver for FX570m?

RMSMajestic wrote:Passing all tests does not implies fully stable.
I tried the 1.05V BIOS a few months ago, under windows 7 everything seemed to work fine. It even passed the furmark.
However under windows XP the screen freezes quite often. And a few weeks later my beloved T61p passed away
FYI, I could overclock my FX570m to 500+mhz before, 3dmark 03 scores abt 12000+
P.S. Is there a way to force install 8600m gt driver for FX570m?

Quick question : your T61p which passed away after a few weeks (after being undervolted) was manufactured later than August 2008 or not ?
I'm trying to figure out if undervolting (too much and/or for too long) could actually kill the GPU which is used in the T61p.

Long story short: I undervolted the GPU on my T61p (manufactured in August 2008) to 0.925v by modifying the mainboard (long before these bioses came out) and my T61p died exhibiting the usual GPU failure symptoms (black screen at power on, few leds lit, CPU fan spins up and down, no beeps). I know the bios is fine because starting the T61p without memory modules installed leads to beeps. Anyway, the thinkpad died either because the GPU died (for whatever reason) or because my wife spilled some milk on it (i cleaned it properly when it happened and it worked ok for a few months until it died).

I managed to get a genuine Lenovo refurb mainboard with a (replaced) GPU manufactured in the first week of November 2009 (week 45, 2009). Now comes the question : should i undervolt the GPU (again) on the refurb mainboard or not ? And if i should undervolt again then by how much ? Is 0.925v safe ? Won't it kill the GPU again (if the GPU died because it was undervolted) ?

PS: the GPU was perfectly stable at 0.925v at all the workload levels (idle, furmark, games, etc). Before the T61p died there were absolutely no signs of the impending failure (no video artifacts, no distorsions, no problems what so ever). The T61p died suddenly, it just wouldn't start one day, it died when starting "cold" so to speak.

As far as i know, undervolting can ONLY make the system unstable - it cannot cause any physical damage like overclock

From Wikipedia:

"Undervolting is a practice of running the CPU or any other component with voltages below the device specifications. An undervolted component draws less power and thus produces less heat. The ability to do this varies by manufacturer, product line, and even different production runs of the same exact product (as well as that of other components in the system), but processors are often specified to use voltages higher than strictly necessary. This tolerance ensures that the processor will have a higher chance of performing correctly under sub-optimal conditions, such as a lower-quality motherboard or low power supply voltages. Below a certain limit the processor will not function correctly, although undervolting too far does not typically lead to permanent hardware damage.

Undervolting is used for quiet systems, as less cooling is needed because of the reduction of heat production, allowing noisy fans to be omitted. It is also used when battery charge life must be maximized."

Overclocking cannot cause any damage either; overvolting can.

QWERTY Andreas wrote:As far as i know, undervolting can ONLY make the system unstable - it cannot cause any physical damage like overclock

I have a FX570m faulty mobo after undervolting, did not do any hardware modification to it.
amwrdfe from 51nb also had faulty FX570m motherboard after undervolting BIOS, although he also carried out the QC mod.
plclife had a faulty NVS140m motherboard after flashing the 0.95V BIOS, he just did the Dual-Core P8800 mod.

In practice low voltage can cause damage. I have a burnt out screen and a broken router that I'm 100% sure they are damaged by low voltage.
Although in these cases there's no way of telling if voltage or nVIDIA is the one to blame. :/

Hello everyone,

I've done some tests on two T61 ThinkPads and found the 0.9V BIOS to be unstable in HTML5/Flash videos playback (YouTube, Vimeo etc.). There were some artifacts in the picture, slow playback performance and a black screen/hang in the end (after a moment or two). On the other hand FurMark went fine on both (but it is only an OpenGL test). The 0.95V BIOS works perfect on both (so far). Thought someone would be interested.

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p.art

0.95v works great for me!