Two months ago I ordered an Intel Mac Mini and told you what I thought about it. I had purposefully opted for the cheaper 1.5GHz Core Solo model. The Core Duo Mac Mini has a 1.66GHz dual-core chip. However, I waited a while, knowing that one could easily upgrade to any Core processor they wanted. With that bit of knowledge I held out until the the prices became a bit cheaper and snatched a 1.83GHz Core Duo the second it was in stock at Newegg.
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Procedure
The disassembly procedure was fairly normal; use a thin, flexible putty knife to separate the top cover from its retention hooks. Remove the four screws around the side of the case, the fan cable, the drive cage, the airport antenna, the metal standoff on the lower left corner, the LED cable, the power switch cable and then pull out the motherboard. I flipped the motherboard upside down and used pliers to lightly pinch the hooks of each of the four white posts that hold on the heatsink. The springs are extremely powerful on these posts so if you're not careful they will shoot across the room after you've disconnected them from the motherboard.
When removing the heatsink, you should be careful not to yank it off because there is a thermal sensor adhered to it which you don't want to remove from the heatsink. On the socket itself, there is a small metal screw which you rotate half a turn counter-clockwise to unlock the processor. After that you can remove the old processor, discharging yourself to some grounded object before handling it, and put in the new processor. At this point I disconnected the thermal sensor cable from the motherboard and scrubbed the heatsink with acetone and alcohol to get rid of the old thermal paste. After drying that off, I locked in the new processor and evenly applied a thin layer Arctic Silver 5 thermal paste to the CPU die. DO NOT get Arctic Silver 5 on your hands, it is a huge pain to remove and can stain carpets if you drop any. In addition, Arctic Silver 5 is electrically conductive so you won't want any of it getting on other parts of the motherboard. Alternatively you can use a thermal paste called Ceramique that has similar thermal properties and is not electrically conductive. You only need a very small amount, too much can actually hurt thermal transfer from the processor to the heatsink. The MacBook Pros suffer from a case of too much thermal paste as someone discovered upon disassembling their MacBook Pro. This is why most MBP's have high temperatures.
All of what I've said so far only took about 5 minutes - if you are comfortable with working on your computer like this it's an easy procedure. However the hardest part was getting the 4 posts with the powerful springs to attach the heatsink to the motherboard. If you have worked with Pentium 4s or AMD Athlon 64s before, you will notice that there is no heatspreader on the Core Duo as there as those processors have. This means that it is actually possible to crack the CPU die without much effort. This is why it is of supreme importance to hold the heatsink steady while fastening each post. Do not do one at a time - try to push in two opposing, yet not adjacent, posts at the same time while applying light pressure to the middle of the die to keep things steady. I used pliers to grip each post and push it in until I heard a distinctive click when the hook had expanded. Explaining this is a little hard but when you come to the point of doing this, you will understand.
From here on out it was just a matter of reconnecting things and putting screws back in. For the beginner I recommend checking out this video from OWC to learn how to remove the Intel Mac Mini's cover and drive cage. For the rest of the procedure, this guide will prove indispensable. If you have any questions along the way, the 123MacMini.com forums are a great place to get help.
Performance
Luckily, everything was done properly and I was greeted with the Apple chime. OS X loaded in roughly half the time, around 25 seconds or so (I believe it used to take 48-50 seconds). I was amazed. I verified everything by going to the About This Mac menu. The mini had correctly verified the processor and everything was working great. iTunes loads completely in one dock bounce - yes, dock bounces are now a method of benchmarking. Photoshop has found much more pep as well.
But this all means nothing without some real numbers right? In the Xbench CPU test my 1.83GHz scored a 69.05 compared to my old 1.5GHz Core Solo's 52.39. A stock 1.66GHz Core Duo Intel Mac Mini gets a 63.61 on this same test whereas Fugger's (the guy from XtremeSystems.org that put a 2.16GHz Core Duo in his mini) computer got a 75.56 on this same benchmark.
I could have held out for an Intel Merom processor which is purported to be 20% faster than the 2.16GHz Core Duo, compatible with the Intel Mac Mini and will be released in August. I chose against this as it will likely be expensive when it launches and I have a summer of photoshop, web development, (attempting) learning Ruby on Rails and watching movies in HD ahead of me. The Core Duo upgrade was definitely worth it. Instead of a solitary 1.5GHz processor, I have two cores making for a 1.83GHz processor powering my pint-sized computer. Along with my 2GB of DDR2-667 SDRAM and 7200RPM SATA 80GB 2.5 inch hard drive, my mini has become less of a laptop and more of a desktop - with the numbers to prove it. If you should have any questions about this upgrade process, feel free to send me an email or drop a comment.