Patches enable Palm Pre CPU scaling, power savings | webOS Nation

Patches enable Palm Pre CPU scaling, power savings

by Derek Kessler Mon, 23 Nov 2009 4:25 pm EST

Palm Pre Rocket

While every update to webOS has brought speed improvements in the form of cleaned up code, Palm Pre phones across the globe have been limited to running at 500 MHz. That is in spite of the fact that that these phones pack a beefy Texas Instruments OMAP3430 processor rated at 600 MHz. What gives? Mostly it’s power management, running at the full 600 MHz will drain batteries darned fast. Over at WebOS Internals they’ve whipped up a group of new patches that not only promise to boost your Pre’s speed, but also to save battery life at the same time. How do they do it? CPU scaling and dynamic voltage reduction.

Before we go any further, these patches carry more risk to them than the standard patch application. As it would turn out, the TI OMAP3430 CPU was purposefully set to 500 MHz by Palm after TI realized that a some of the early chips couldn’t handle the full 600 MHz. These chips had their useful lifespans reduced to less than six months. While there aren’t a lot of these chips out there, Palm was the first manufacturer to use the chip, and it’s enough of a concern that they’ve chosen to not let it run at full bore (the chip is also used in the Motorola Droid and Nokia N900).

While most users will reap benefits from installing these patches, there is the chance that - like some members of the PreCentral forums - installing these patches may seriously brick your Pre. Also, one should not install more than one of these patches at a time, doing so will likely result in serious borkage. We are tinkering with the processor here, folks, so tread lightly.

All of that out of the way, here’s the scoop. There are four patches: Powersave Smartreflex 500MHz, Powersave Smartreflex 600MHz, Powersave CPU Scaling 500MHz, and Powersave CPU Scaling 600MHz.

The 500 MHz patches don’t set the Pre’s top clock speed any faster than it is now, limiting the chances of damage, while the 600 MHz patches unlock the CPU’s full potential. Running the Pre at 600 MHz will drain the battery faster than at 500 MHz.

The Smartreflex patches activate a technology built into the TI OMAP3430 chips that allows it to dynamically lower the voltage when not running at full throttle. Unless you’re running your Pre at full power at all times (and getting two hours battery life while you’re at it), this will result in significant battery life gains as the CPU’s power draw will drop when idle.

The CPU Scaling patches, however, run the processor at full voltage but instead dynamically scale the clock speed from 250 MHz up to your chosen maximum. These patches take advantage of the capabilities of the Linux core underlying webOS. Running the CPU at a lower clock speed will also result in notable battery life improvement. There can be some stability issues with CPU scaling, but most users have reported smooth sailing.

Before installing any of these patches, be sure to read the description - there are multiple versions of some; older versions specifically say obsolete.

Again, we need to emphasize that the TI OMAP3430 in your Pre may not be able to handle the 600 MHz patches. If you don’t feel like living on the edge but still want to reap the benefits of Smartreflex or CPU scaling, go with the 500 MHz patches. Also do not install more than one of these patches at a time, if you decide to change to a different patch, first uninstall and restart your Pre (not just Luna).

For what it’s worth, this blogger has installed the Powersave CPU Scaling 600MHz patch and has been humming along nicely. The phone overall feels much smoother and a touch faster, while apps like Photos and Music along with Universal Search are notably faster. Whether my Pre will be up to the task over the long haul remains to be seen, but for now I’m living on the edge in the bright shining land of CPU scaling. If you’re feeling up to the task, fire up your preferred patch installer and get patchin’.