Replace Your Laptop's CPU

Before you remove your first screw, it is critical that you upgrade your BIOS to the latest version. Manufacturers often update BIOSs to allow support for newer CPUs. If you upgrade to a chip that's newer than your BIOS allows, your notebook won't boot at all. Check the support section of your manufacturer's Web site for any BIOS updates for your notebook.

The process for upgrading your CPU is usually almost identical to that for upgrading your graphics board. In the case of the Inspiron E1505, the CPU resides directly underneath the video card assembly, so disassembly instructions are exactly the same for this part as for that one.

Laptop designs vary, but the upgrade process usually begins with removing hinge covers: Pry up any plastic hinge cover and pull it away from the chassis. Avoid excessive force, as pulling too hard can break the plastic parts.

Detach the keyboard by taking out the screws beneath the hinge cover that secure it, lifting it off, and then unplugging the connector. On some notebooks, simple latches allow you to remove the keyboard without unscrewing anything.

(Note: In a job like this, keeping track of where each screw came from is important. A good way to keep things organized is to use paper cups to hold the screws--one cup for each step of disassembly--and label each cup clearly.)

Remove the display assembly--the entire apparatus of the screen--by taking out the screws on the bottom and back of the portable, and unplugging the video and Wi-Fi antenna cables (pictured).

Next, pull out the optical drive; this usually means depressing the latch on the bottom of the laptop and sliding the drive out sideways.

Remove the upper shell by taking the screws holding it out of the bottom of the PC. As you lift the shell off of the chassis, make certain that no part of it is still attached to the bottom of the case or to the motherboard. If it feels like you have to force it, that probably means either a screw is still in place or a clip remains to be unsnapped. Before continuing, back off and double-check your service manual to discover any well-hidden screws that may have eluded you.

We've now reached the part of the upgrade that involves actually laying hands on critical system components, so be sure you're wearing an antistatic wrist strap and are well grounded before continuing. Obviously, you'll have to use care in handling any components that you touch.

On our laptop, the preceding steps gave us access to the graphics card assembly, which we removed by loosening two screws. The CPU sits beneath that card.

With the graphics card out of the way, we removed four more screws to get the heat sink off and to expose the CPU itself, held in its socket by a single locking screw.

Turn the CPU socket's locking screw counterclockwise until it stops, and lift the CPU straight up and out of the laptop. Drop the new CPU in, but don't push it (if it looks as though it needs a push, it isn't aligned properly). Turn the screw clockwise to lock it. Note: Some systems use a locking bar in place of a screw.

Next you need to prepare the heat sink anew: Remove all of the old thermal compound (silver-gray gunk) by wiping the heat sink with 99 percent isopropyl alcohol and a lint-free rag. If you bought a used CPU, it may be covered with this goop, too, so clean it off as well. When it's dry, reapply a paper-thin layer of thermal paste to the top of the CPU, spreading it evenly with a business card or an old credit card.

Clean up any excess paste and replace the heat sink. Reassemble the laptop and boot it up. Jump into the machine's BIOS setup to make sure the laptop is seeing the CPU properly. Finally, launch Windows and enjoy the performance boost!