I have successfully brought the Tegra 2 in the Xoom to 1.5GHz. A few kernel modifications make the dual core chip in the Xoom even more powerful than the recently announced Tegra 2 3D! 1.5GHz through two Cortex A9 cores is truly a force to be reckoned with.
2/28: Applied L2 prefetching patch. This increases Linpack to about 63 MFLOPS @ 1.5GHz. Flash the kernel and push the wifi module again: http://www.setcpu.com/files/xoom_ocboot_v2.zip (thanks ccfries for the heads up!!!)
1. Make sure you've unlocked your Xoom's bootloader for flashing first, then root it.
2. Grab this zip and extract it. It includes a boot.img with the overclocked kernel and a corresponding wifi module: http://www.setcpu.com/files/xoom_ocboot_v2.zip. Thanks to Koush for the rooted ramdisk in this boot.img!
3. Reboot into the bootloader by running:
adb reboot bootloader
4. Flash the boot image to your boot partition, then boot back into Android by running:
fastboot flash boot xoom_ocboot.img
5. Push the bcm4329.ko to your /system/lib/modules folder and reboot to re-enable wifi:
adb push bcm4329.ko /system/lib/modules/bcm4329.ko
The usual disclaimers apply here. Only do this if you know what you're doing. Though the long term stability/reliability of similar overclocks on other Android based ARM devices is known, this software is provided with no warranty, and I can't be held responsible if you fry your Xoom or anything.
The kernel defaults to 1GHz max for safety, and also includes 1.2GHz and 1.4GHz steps in addition to the 1.504GHz step. I've also updated SetCPU to support the Xoom, so grab that (I know the interface currently looks bad on the Xoom; a tablet optimized interface is coming soon!). SetCPU versions prior to 2.1.1 will not work for setting speeds on the Xoom.
Source code: Based on Google's android-tegra-2.6.36-honeycomb with some overclock specific modifications by me.
I get ~47 MFLOPS in Linpack for Android, 35 MFLOPS stock. Linpack seems to hit a wall somewhere and isn't really accurate for the Xoom:
I get ~355ms in SetCPU's native bench (C only, the Tegra 2 sadly doesn't support NEON), ~534ms stock. This scaled almost precisely with clock speed, but the native bench isn't multithreaded:
3105 in Quadrant at 1.5GHz, compared to 2226 stock (though Quadrant tests more than just the CPU):
Keep in mind that the benchmarks I tested often aren't multithreaded enough to show a large difference between the Xoom's Tegra 2 and a similarly clocked single core Cortex A8. Some operations benefit more from the Cortex A9's improved architecture and/or the two cores more than others.
Enjoy your even faster Xoom!