Comment 42 for bug 760131

This is the reason why there should not be a Generic kernel. This kernel in contrast of server kernel, is the same for Desktops, Laptops and Netbooks.
The server kernel is optimized for server purposes, whereases the generic kernel is the same for Desktop and Mobile PC's (Laptops/Netbooks). Unfortunately the Desktop PC is not the same with the Mobile PC's. Desktops don't have consumption problems but Mobile PC's do have.

We can not demand the generic kernel to behave in the same way in Mobile PC's as it behaves in Desktop PC's. That is why personally, after a fresh install of a new Ubuntu version, I recompile the generic kernel with options that are best for my Laptop:

-- Conservative Governance (default is performance that drains my battery and produces unnecessary heat )
-- 1000hz cycle (if I recall correctly default is 250Hz, which creates more wakeups for CPU)
-- Core2 Family (optimized for my i7core CPU, to remove any unnecessary generic code from kernel )

The above are some of the ways that I have accomplished better battery life and less heat on my Laptop.
IMO, there kernel team should pack Ubuntu kernel in 2 flavors (as they did for server edition):
--Desktop PC optimized options Kernel
--Mobile PC optimized options Kernel