I started working on the PMS board but decided to run some tests on the Wii first.
This project will be the first portable to feature a Wii Mini via an OMEGA trim to take advantage of the Hollywood-2 GPU.
For those of you who don’t know, certain revisions of the Wii Mini feature a newer die shrunk GPU (compared to the regular 4 layer Wii) called “Hollywood-2”. I go over further details in my other thread here:
https://bitbuilt.net/forums/index.php?threads/project-m.5113/post-54897
Shank did some testing a while back to see the lowest voltages the Wii can go. According to the numbers Shank has reported, we can theoretically undervolt, but doesn’t seem like anybody has ever done it in a portable nor reported some concrete numbers of power consumption. I want to add to this so we have some documentation.
Keep in mind the testing has been done on a Wii Mini with 1 Wii remote connected on the Wii menu screen. The values of a regular 4 layer Wii will be different. I may be able to go lower, but probably won’t go much lower for piece of mind.
The Wii Mini draws about 4.124W (on the Wii menu screen) with custom regs and standard voltages (1V, 1.15V, 1.8V, 3.3V).
I need 3.3V for most things in the portable as well as 1.8V so I won't be messing with those.
I started with the 1.15V line which normally draws 1.62A (1.863W) and took it down to 1V (under load) which now draws 1.36A (1.36W).
According to Shanks notes, we can go down to 0.916V. Will test that later.
The 1V line normally draws 1.16A (1.16W) and took that down to 0.875V (under load) which now draws 1A (0.875W).
According to Shanks notes, we can go down to 0.867V. I'm going to leave this one as is since it is already close to the lowest it can go.
By undervolting these 2 voltage lines, I am saving an additional 0.788W, for a grand total of the Wii Mini drawing only
3.336W!!!
I will still try to undervolt the CPU more and see what happens which I will update later. I haven't grabbed the numbers in game since my multimeter is acting up now, but shouldn't be too far off. Have been running Melee with 4 CPUs on the hardest difficulty for 2 hours now, no issues. I can confirm the undervolt at these voltages at least for the Wii Mini.
EDIT: I was able to get the total power consumption to just 3W, but the system was unstable, and would not last a few minutes without crashing. The GPU did boot at 0.8V under load but I didn’t try going any further since there’s no point for stability reasons and same with the CPU, which the lowest was able to boot was 0.97V. So far the best combo I have found was my first initial test of the GPU at 0.875V and the CPU at 1V. I did a pretty crazy stress test and left Melee on overnight with four CPUs at max difficulty, and a few hours in it did crash. But let’s be honest, with portables that’s unrealistic. Just in case I will increase the GPU to 0.9V. Regardless, a great saving in power!
