Well, it's not a PPC Mac, but it's their next closest neighbor: the slowest Intel Mac ever made. That's right, it's a first-generation AppleTV! I have mine on 10.5.8, so it has similar software limitations to a PPC Mac. However, the 256 MB RAM (soldered to the motherboard) really hobbles the machine and makes it almost unusable. Almost.
I redid the thermal paste on both the CPU and GPU, which are connected directly to the external casing as a huge metal heatsink. I installed OS X on the machine years ago, and porting the install over to a 32 GB SSD I had sitting around was simple using carbon copy cloner. The SSD is much cooler & quieter, so I also removed the fan.
With SSD and no fan the machine uses about 15W from the wall no matter CPU load, which is less than I expected considering how hot the machine still gets to the touch. With the original HDD and fan installed power consumption was closer to 22W from the wall.
I can get onto the internet through Terminal using the Links2 text-based browser. It's FAST, but a real pain and very slow to navigate. The RAM limitations (typically 15-50 MB free after Mac OS and Finder) prevent me from running any browsers in GUI-mode.
I can do reasonably advanced word processing using Bean. It can read and write doc and docx files, so that actually lets me get most of my work done.
I haven't figured out a good e-mail client that A. has a RAM footprint < 50 MB, and B. will work with gmail. Any suggestions?
-update: picture of the setup
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