T61 Nvidia GPU undervolting: success!

This is my re-post from thinkpads.com

Recently I had finished a project on building a T61 15” Flexview Frankendpad.
The donor T61 is 8889-ACG and unfortunately it has dedicated NVS-140M GPU. Comparing to Intel X3100 integrated video it has some serious drawbacks:
- It is prone to Nvidia GPU bug with bumping material.
- It consumes a lot of power: at idle my T61 FV consumes 14.3W with all off, backlight at lowest level, and Powermize is on max battery. While another T61 15.4” WXGA with X3100 GPU consumes only 9.5-10W. Take into account that my Flexview UXGA requires 1-1.5W more than the 15.4” WXGA, I estimated that the Nvidia GPU consumes about 4-5W at idle, while the Intel one consumes about 1-1.5W.

So my biggest concern is to lowering power consumption of Nvidia GPU. Using Nvidia Inspector and NVPMManagerUni, I set the GPU at fixed max battery level and underclock the GPU a bit, to 130Mhz. However, the power consumption was still high because the supply voltage for GPU was still 1.15v. Therefore, my next objective is to lowering the GPU voltage.

However, unlike CPU voltage, the mobile GPU voltage can not altered by software. Some PC video card can change voltage by altering the so called voltage table in its BIOS using NiBitor software, but this software does not recognize mobile video card where video BIOS is integrated with main BIOS. Therefore, the only way I can go with is to make hardware mod in the GPU power supply system.

Studying T61 schematics, on page 85 I had found that Lenovo uses ADP3209 IC to control the voltage of GPU. This IC has 5 VID pins (like CPU power supply systems). Before going into action, I tried to overclock my GPU, and it could go as high as 650Mhz at 1.15V. So my estimation is that it can keep the default frequency of 400Mhz at about 0.90V. Based on that, I decided to give the VID3 voltage level of 1 instead of 0.

To do this mod, I removed the 0 Ω resistor R590 from the board to give high (1) signal level to pin 26 (VID3) of the ADP3209 IC. However, due to unknown at this moment reason, the voltage at this pin is still low (0). To cope with it, and due to the fact that before I accidentally remove R537, I connected pin 26 to pin 27 (VID2) and they both have high level. The GPU voltage after this mod is 0.95V for Powermize lowest performance level (before: 1.15V) and 0.90V for highest performance level (before 1.20V). You may find strange that the latter voltage is lower than the former

The laptop boots without problems, at 0.90V I even can overclock the GPU a bit, up to 450Mhz. Using Video Stability test, I had found that the GPU temperature droped by 8-10 degrees Celcius (from 74deg to 66 deg according to GPU-Z, or from 65 to 58 deg according to TPFan control). Another effect is that at idle, the laptop consumes only 13.0W instead of 14.3W before the mod. Thus, the battery life on my 9 cells 77Wh battery is extended by 10%, up to 4.5 hours comparing to 4 hours before. Hope that with lower working temperature, my Nvidia GPU will work longer

Here are images of ADP 3209's VID voltage table and part of T61 schematics. The actual picture of mod will be posted later.

 

Impressive work. You can see the heathy voltage margin provided to the gpu. Usually CPUs are also overvolted beyond their needs. Your technical expertise means you could consider a companion guide to overclock the cpu based on the info in Lenovo/IBM T61 FSLx PLL pinmod.

The dual-IDA + PLL pinmod would extend the longevity of these great systems. Your T9300-2.5/2.7 would be running at 3.33/3.59Ghz, which is comparable to i5 cpu levels.

 

Hmmm, I don't quite understand how you modded your hardware to lower the GPU voltage, but congratulations on the mod! From What I have seen, GPU voltages can be easily modified with Nibitor with many notebooks, but I suppose there are always exceptions, in which case you have to find other way around.

I find it odd why you give more voltages to the lowest performance level than the highest level, if the GPU remains stable at 0.9v when stressed, why give more than 0.9 to the lowest level?

 

I don't have much motivation to overclock CPU due to the 2 facts:
- I tried to do PLL pinmod on my previous T60p but the laptop did not even boot. My guess that the BIOS on T6x series does not allow for CPU FSB frequency change. Note that X-series are overclocked easily while there no precedence of overclocked T60 or T61.
- My T9300 at 2.7Ghz requires 1.1V to work stable (while at 2.5Ghz requires 1.0125V). My calculation shows that at 2.9Ghz it will require about 1.25V. It is too high and my cooling system will hardly cope with it.

 

Nibitor does not allow for altering voltage table of my BIOS (I used Phoenix BIOS editor to decompose Lenovo BIOS and then open it in NiBitor). Moreover, I think that playing with BIOS without specialized facilities is a very dangerous business.

The voltage in minimum performance level is higher than that in maximum performance level can be explained in the updated VID table in my first post. Before the mod, VID2 = 0 for max perf. and =1 for min perf. I set VID3=1 to lowering voltage by 0.2v, VID2=1 to lowering it by another 0.1v. But in min perf. mode VID2 already =1 so it has no effect, i.e. only VID3 has effect.
Another way to explain: please, look at the value(s) of VID1 in that table.

 

congrats.

I run mine at 625MHz core and 950 memory. For over 3 years I have had no problems, thus no intentions of actually undervolting the GPU.

the max it can run is at 650/975

I think the 140m on the 15" thinkpads were using 256MB memory. Maybe those were the ones that would hit the dust often. Mine is a 128MB version, no issues so far.

 

I'm trying to overvolt the 7150M on this laptop and I don't understand how to do it with the voltage table and all that? I keep getting an error about them not being correct. On 3d it says 1.2V. I'd like to up my 3d volts to 1.25-1.3V... I don't understand how to do it.

I'm having issues with my tl-60 overclock when at 2.5Ghz from 2.0Ghz it runs cool under intelburntest at 68*C and ocasionally the "cpu" temp will spike to 98*C for a split second. The Cores are still at 68-69*C when that spike occurs. Maybe it's the voltage regulators overheating? Anyway it'll pass sometimes and sometimes it'll fail. I suppose 2.427Ghz may be the stable max however in game 2.5Ghz runs great. I'm using GPU-Z to pull video bios, and CrystalCPUID to adjust cpu voltage. At 2.0Ghz it uses 1.150V I believe. I pushed up to 1.325V and it didn't break 75*C and wasn't stable. However in game it's stable. I like to pass intelburntest though. Anyway I need more gpu clock. Maybe 1.35V on the gpu core to push to 650Mhz. The 7150M has a hard time with heavy geometry.

I wanna overvolt the gpu since when i overclock to 575Mhz from 425Mhz it becomes unstable but it's only at 63-65*C when at 575Mhz. I need to over volt the bios so I can push it to 600Mhz stable hopefully and still stay below 70*C on the GPU.

I modded the laptop bottom plastic to let the fan breathe and it dropped temps about 30*C since the fan was restricted from lack of design.

*UPDATE*

Installed copper shim on cpu and i'm only hitting 58*C on intelburntest with the 500Mhz overclock totally stable. I'm running the 7150M at 560Mhz core clock totally stable and running pretty damn good i must say! Kills an X3100 by far! Just need to overvolt so I can run 650Mhz+. At 560MHz core clock I'm seeing 73*C in 3dmark03 on the top end. I could see it going to 75-78*C with an overvolt and overclock to 650Mhz without a problem. The 7150M isn't that bad at all!

I'm thinking about getting a TL-68 2.4Ghz for $75 and push it to 3Ghz hehe.

7150M - 3dmark03 - Battle Of Proxycon - 15fps avg
GTX 470 - 3dmark03 - Battle Of Proxycon - 5,000fps avg lol

 

great work, always wondered if this could be done.

 

I successfully overclock my T61. Now I have a T8300 running stable at 3.2Ghz@1.2v.
Long story. I will report about it later when have enough time.

 

so you pulled down that pin on the clock gen to start using 266MHz bus instead of the 200MHz one ?

12x 266 would be 3.2GHz, as far as I can see the things, heh.

nice