Just as the disclaimer for Jackass: The Movie says: This stunt was performed by a professional, so neither you nor your dumb buddies should try anything shown in this how-to.

 

WHAT YOU NEED

> iMac with Intel Core Duo processor

> Intel Core 2 Duo Processor (we used a T5600; $249.99, www.newegg.com)

> Torx screwdrivers #6, #8, #9

> Phillips screwdrivers #1 and #2

> Credit card or similar plastic shimmer

 

So you jumped on the Intel-Mac bandwagon too soon and now your Core Duo-equipped iMac feels inadequate? We're here for you, friend, with a step-by-step guide for something that, in retrospect, we'd actually recommend you don't try: replacing your iMac's Core Duo processor with a Core 2 Duo chip.

 

Why the upgrader's remorse? Would you attempt brain-transplant surgery on your brother? That's kind of how this feels. So we respectfully suggest that you enjoy this pictorial as infotainment only. And if you must try it yourself, know that different-model iMacs may have different screw layouts on the motherboard, and you may also encounter differences en route to the board as you're disassembling the casing (not to mention that it'll instantly nullify your warranty).

 

Still here? Before you start, clean off a large, static-free tabletop and gather up the tools listed. This is a very complex project that you might need to leave overnight, so the kitchen table isn't the best choice.

 

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Step 1: Crack the Case

 

First remove the RAM-hatch cover by unscrewing its two screws - note that they're captive screws, so you can't completely remove them. Remove the RAM module(s) inside and tuck the levers all the way into their slot. Remove all of the other screws on the bottom of the iMac and work the outer bezel loose from the bottom. Angle the back piece up a bit, but don't remove it yet. First we need to release a couple of hidden latches at the upper edge.

 

Mind the RAM-lock levers-you're removing the slot that they poke through.

 

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Step 2: Pop Two Latches

 

This is one of the trickiest parts, so steel yourself. With the iMac face-down, lift up the rear piece of the case slightly from the bottom. Wedge a credit card up and into the far-right side of the vent slot, as indicated in the photo. Look all you want, but you can't see the latch that you need to hit with the card. Instead you'll have to feel for it; it's about 2 to 2.5 inches from the corner.

 

Got it? Good, now get the one on the left-hand side. When you think you've released both latches, start angling the back piece up from the bottom, and if you hear some nasty crunching, try again with the credit card. Once you've sprung both latches, pull the back up and out, pivoting against the top. Take it slow until you see wires for the iSight camera and microphone, which you should then carefully disconnect.

 

Like opening a car with slim-jim, this procedure gets easier with practice.

 

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Step 3: Free the LCD

 

Peel back the silver tape and black shielding from the LCD carefully. Seriously: You're going to replace the LCD, so try not to mangle the tape and shielding too much. A plastic picnic knife - or a proper spudger stick, if you have one - helps. Then find the four Torx screws indicated in the photo and remove them. Tilt the LCD up a bit from the bottom edge and disconnect both the video cable and the power inverter cable from the motherboard. Feel free to remove the right-side speaker block for better access - you'll have to in the next step anyway. Now set the screen aside and take a coffee break (optional).

 

Tip: Take a glue stick and dab glue onto the tip of your screwdriver to make it easier to replace these screws later.

 

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Step 4: Pull the Plugs

 

Before you start removing plugs from the motherboard, do yourself a favor and take some photos of the board with everything plugged in. Also note the cable routing. If you're the cautious type - except we know you aren't because you're undertaking this project - take individual shots of each plug's neighborhood to make sure you remember how to reconnect everything correctly. Now proceed to unplug everything from the motherboard. Caution: This is extremely delicate work - and if we have to tell you to pull on the plugs themselves rather than on the wires, perhaps you should abort now before doing (more) serious damage to your iMac.

 

The plugs are even more delicate than they look; we broke one and had to make a permanent connection with the soldering iron.

 

Step 5: Selective Screw Removal

 

Remove the screws circled in yellow in the photo for step 4 (above). Be sure to mark each screw with its location to spare yourself big headaches later. Do the same for the AirPort, Bluetooth, and IR modules. Don't touch either of the pieces that look like heat sinks (as indicated in our photo): One stays put, and the other we'll free up from the backside in a later step.

 

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Step 6: Pry Out the Motherboard

 

The board is flexible, but its electronic components, connectors, and solder are not, so if you bend the board too much, you'll probably break something loose, if not break it outright. So start by wiggling the board gently up from each side to identify any sticky parts, and then carefully work it loose. Before you remove the board, look on the back and find the power supply connector and unplug it. You may also need to disconnect the hard drive back here, depending on your model of iMac. Now set the motherboard upside-down on your static-free surface.

 

There's one more connector to unplug - and it's a big one.

 

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Step 7: Heave the Heat Sink

 

Under that very large heat sink/fan/cooling pipe rig sits the processor. Find the corner bracket at the end of the cooling pipe assembly and remove the single screw at the end, leaving the two in place on the upper piece above it. (Note: You can't see those two screws in our photo because the board is upside-down, as directed in the previous step.) Loosen the four screws on top of the heat sink a little, then flip the board over and remove the four Torx screws from directly behind the heat sink screws. Flip the board over again and gently remove the entire cooling rig. Warning: When you're done, reassembling the cooling system seems straightforward, but we assure you, it is a feat of manual dexterity.

 

Putting this rig back together is pure fun. (By fun we mean excruciating frustration.)

 

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Step 8: Plug in More Power

 

Turn the processor socket's lock screw a half turn to the left to release the processor's pins, and gently lift the processor straight up and out. Note the placement of the labels on the chip and insert the new processor in the exact same orientation; press on the processor a bit to make sure it's properly seated, and turn the lock screw back a half turn to seal the deal. Use a bit of rubbing alcohol to clean off the bottom of the heat sink and apply a small dab of thermal compound - about the size of a BB - to the mirrored part of the chip.

 

Now reverse the procedure to stitch your iMac back up. Remember: All those little connectors and all their little wires need to be put back precisely in the right spots or they may get crimped or broken when you get to the last triumphant step: snapping the case back together.

 

More thermal compound is not better in this case - too much can raise the temperature, not lower it.