After overcoming the FS key bug a few months ago, my latest efforts have been on increasing performance while running Linux on my Sony Vaio FS760/W .
Strangely, when my laptop was plugged into the wall via the AC adapter - Gnome System Monitor would indicate that my CPU usage (while idle) hovered around 20% utilization, and would erratically spike up past 60% for seemingly no reason. Performance was laggy, but unplugging the ac adapter would bring everything back to a normal state.
A really simple test to try if you are experiencing similar trouble on your Vaio running Linux is to open up a terminal and hold down a key. Whatever letter you are holding down will slowly creep across the terminal - now unplug the power while still holding down the key. You should see things smooth out drastically.
Doing some additional research around the Ubuntu Linux bugtracker - I realized that this may not be a Vaio compatibility problem as much as it is a bug with Centrino chipsets in the Ubuntu Generic kernel. As an experiment I installed the i386 architecture kernel, and the difference was night and day. While idle, cpu usage in Gnome is less than 2% and the system is running smoother than I ever remember it being. Shortly after, I removed all references to the generic kernel from my system and haven’t looked back.
Making this change did prompt me to redo my graphics and FS key settings, as the functionality of both is directly linked to kernel modules. My Geforce 6250GO was brought back online via the Envy script (which is awesome, and incredibly simple if you haven’t tried it) and I brought my FS key support back via my feisty-fsfn script previously published. However, changing the architecture to i386 caused my original script as written to fail due to a typo. I’ve fixed this and uploaded a correct copy.
Please let me know if you have any additional insight or experiences with this issue regarding Linux on Vaio laptops!