Paginate Processor Load

Having recently moved a development from a Windows-based to a Linux-based Apache (MPM) platform, I find that the pagination function appears to cause a particularly heavy load on the processor - and this is with a tiny test data-set.

Although I appreciate that some of this is likely tied into the particular implementation of Apache, I do recall being particularly concerned as to how much data potentially needed to be processed with each page-flip when I first started using CI's paginate() and making a mental note to keep my eye on it.  I hadn't expected it to be quite so soon...

Has anyone else noticed this... or perhaps experienced it crippling a production site under load?

Comments and thoughts would also be appreciated, thanks.