Replace your laptop's CPU

Saddled with an old, slow processor in your laptop? Ripping it out and subbing in a new one can result in an exceptional boost in speed. For instance, upgrading from a 1.66-GHz Intel Core Duo to a 2-GHz Core 2 Duo T7200 raised our laptop's WorldBench 6 score from 57 to 68. But this upgrade isn't as simple as most of our other notebook upgrades.
Make sure that you buy a CPU that will work with your portable. In fact, some laptops have nonreplaceable, soldered-in CPUs.
If the processor is upgradable, you'll need to find a compatible replacement. As with a laptop graphics card upgrade, the best way to proceed is to look at what CPUs have been sold with your laptop over the course of its life span, by googling "[your notebook model] CPU." We purchased a 2GHz Intel T7200 from a niche online reseller (we have yet to find a laptop vendor that will sell us a new processor).
Be sure to consult your laptop's service manual (which you should be able to download from the manufacturer's support page) before attempting to open up your machine. Also, make sure to guard your hardware against possible electrostatic discharge by wearing an antistatic wrist strap whenever you handle any internal components.
Estimated Time: 60 Minutes; Difficulty: Hard
Photograph: Charlie Nucci