Xperia Z, Cyanogenmod and Undervolting

By | September 12, 2013

If you’ve read my previous posts, I was using PAC-Rom but recently switched to Cyanogenmod 10.2 Nightly builds, which are Android 4.3.

Device: Sony Xperia Z (16GB White)
ROM: Cyanogenmod 10.2
Kernel: MEOW-Kernel
Apps: TricksterMod and Stability Test

Since I am using the kernel from jeroenqui I will try and keep this post updated with new kernel builds as he updates his ROM, you can check his thread out over here. I take no credit for the kernel, or any issues you may have from flashing the kernel. It should work on AOSP / CM / PA ROM’s based on Android 4.3.

I then used TricksterMod to change governor to wheatley, scheduler to row, enable fast charge and undervolting, I have also disabled doubletap2wake and slide2wake. I have the CPU set from 384Mhz – 1242Mhz, GPU set to 200MHz and Multicore Power Saving set to 2. I then ran the following Stability Test’s.

  • Classic Stability Test for 30 minutes.
  • CPU+GPU Stability Test for 20 minutes.
  • Scaling Stability Test for 20 minutes. (384Mhz – 1512Mhz @ 15 seconds per frequency).

There was no freezes or reboots, however I seem to be able to undervolt more on CM / MEOW-Kernel than previous PA builds.

As for undervolting, my CPU is a “PVS-3”. Taken from this post you can check what PVS revision your CPU is.

The Qualcomm (S4 Pro) SoC has 4 different variant. Slow, Nominal, Fast and Faster (0, 1, 2, 3) . Faster variants can undervolt a lot lower than the rest, or it should already be pre-configured automatically at a lower voltage like the Nexus 4, so some Xperia Z will have less heat and perform better in battery life. For example, for nominal variants, they might only be able to undervolt around -100mV while faster variants can undervolt around 175mV – 250mV.

Voltages (Frequency = STOCK = MINE)

  • 384000 = 850000 = 700000 (-150)
  • 432000 = 875000 = 700000 (-175)
  • 486000 = 875000 = 700000 (-175)
  • 540000 = 900000 = 700000 (-200)
  • 594000 = 900000 = 737500 (-162.5)
  • 648000 = 925000 = 737500 (-187.5)
  • 702000 = 925000 = 737500 (-187.5)
  • 756000 = 975000 = 737500 (-237.5)
  • 810000 = 975000 = 750000 (-225)
  • 864000 = 1000000 = 762500 (-237.5)
  • 918000 = 1000000 = 775000 (-225)
  • 972000 = 1025000 = 800000 (-225)
  • 1026000 = 1025000 = 800000 (-225)
  • 1080000 = 1075000 = 925000 (-150)
  • 1134000 = 1075000 = 925000 (-150)
  • 1188000 = 1100000 = 925000 (-175)
  • 1242000 = 1100000 = 925000 (-175)
  • 1296000 = 1125000 = 937500 (-187.5)
  • 1350000 = 1125000 = 937500 (-187.5)
  • 1404000 = 1137500 = 962500 (-175)
  • 1458000 = 1137500 = 962500 (-175)
  • 1512000 = 1150000 = 987500 (-162.5)