I had been planning on converting a G4 Cube into a Windows7 Media Center for a while and it was quite fun shopping for the parts and researching it. I love the design of the Cube but generally hate Apple. Apple makes good aesthetic cases / hardware but the internals suck (not even mentioning the software)..This is the best of both worlds to rip out the guts and replace them with PC guts. There has been a handful of people that have gone before me with some good results but mine is slightly different and I feel superior in allot of respects mostly because of the latest available hardware.
The motherboard is the foundation of this setup and requires an MINI ITX form factor board. CRAMMED with features is definitely the way to go on the motherboard because you don’t have any room for additional items. I went with a relatively new motherboard from ASUS the ASUS M4A88T-I Deluxe.
I am a fan of AMD for cost and performance and last time I checked the integrated video was pretty good. This board is based on the AMD 880G chipset and has an on board Radeon 4250 with HDMI out 
which is key with this space constrained setup. The board specks call for up to 95watt CPU design which allows for a wide range of processors. It also had a built in wireless B/G/N card with dual antennas that is also one less thing I would not have to fit in (with modification). Some of the other key features are Sound, Bluetooth, ESATA, USB3 and all for 125$. The board mounts quite well as shown when you use 1.5 inch stand offs and drill and tap holes where it mounts. Since the cube board did not truly follow the mini ITX size (Apple .. go figure) you do have to cut a little bit of metal to make it clear.
I ordered two processors, a 45watt 2.8ghz Sepron and a 65watt 3.2ghz Athlon2 dual core. After I got the computer built I switched the processors a few times and decided to go with the 3.2ghz. The Sempron just had to work too hard and I averaged 70% utilization when watching a streaming Netflix. The Heat was a concern but it seemed like a wash because the Sepron working really hard seemed to produce as much heat as the 3.2ghz while not being as taxed. The core unlocker feature did unlock another core on my CPU but it did not make a big enough difference.
The power supply is also a key component for this project. You literally cannot fit a regular power 
supply in this case so I learned about DC power supplies that have an external AC to DC adapter just like the original Apple G4 Cube. The power supply connects directly to the motherboard then to the external power brick from a power jack that fit perfectly into an unused hole in the bottom of the Cube. To make this fit in the case I had to use an ATX 20/24 pin converter-extender and then use some amazing double sided tape to mount the board up against the frame. While this is not ideal it does seem to hold it quite well and does not budge when I touch it. The power supply I got is supposed to handle 150watts and my whole system under complete stress only hit 110watts so it was perfect. Normally the system is 50-70 watts.
It was important to me that it had an internal tuner for basic cable and this was the only extra thing that I put in. I have since learned about network tuners from SiliconDust and may try that route in the future but for now this works perfectly with the only PCI express slot and a flexible extender to mount it in the only place you can. I went with the Hauppauge 2250 and get a fair amount of digital/HD and analog channels. To mount it I had to drill holes in the bottom and torque an nut down to hold it in place. I did make the mistake of putting it to close to the locking mechanism (in the center ) for the case to attach to the acrylic shell but it later worked itself out with the addition of a fan that pushes it over a bit.
What good is a Media Center without a Bluray player? I don’t know because I would find that unacceptable. The original Cube has a slot loading DVD that pops the disks out the top like a toaster but .. of course it is not a standard size. There are some Slim line Bluray slot loading drives on Ebay for about 75$ but then you are left trying to get it to mount and line up with the slots in the exterior. There is a guy on Ebay that is selling an adapter plate for 150$ but he is smoking crack if he thinks it is worth 150$ to be able to mount a drive (twice the cost of the drive). There is a guy on Cubezone that makes inserts to hold slim line drives in the space and he only charges 20-30$ and they work just fine. you would also need the power adapter for slim line as it is smaller than regular sata power connectors.
The Wifi Board on the motherboard put the antenna connectors facing the outside of the IO plate and 
while it does make sense I wanted them to be completely internal. I took the connector off the board with a soldering iron and pointed them back to the inside of the case. the antennas come with big plastic rings around them to set them on your desk or wherever but they fit into the cube after you take all the unneeded plastic off of them. There is a space in-between the Drives and the drive bracket where I just shoved them and it seems the reception is OK. The original cube has a spot for the antennas on the lower sides and that area is plastic instead of metal and that is probably the best spot but they did not fit there. I may try to make them fit there in later builds.
The motherboard takes SODIM DDR3 memory and this is not a big deal really. SODIMs are smaller (plus) and may be a little bit more money but not much. I only went with 2gig and thought it would be enough until I started running Windows Home server in virtual PC so I will probably up it to 4Gig but normally 2gig is fine.
Another key feature is remote control. since the case is plastic I have the remote control IR sensor mounted up under the case where it is suspended and works fine through it. The end result is that there are no extra cords running anywhere just underneath where it is out of the way.
All assembled heat was an issue, I had it shut down on me once (with the Sempron) because there was just not enough upward air flow to remove the heat like the case was originally designed to do. I put another fan blowing air out the top and it has been fine ever since. It reached 60C in a stress test and is a bit warm but not too bad. The Motherboard has a Qfan feature that makes it pretty dam quiet so I am ok with it and I can run a bigger CPU if I decide I want to.
The only disappointment I had was not being able to get original the touch sensor( on/off switch) to work. I spent probably 25hr working on it and while the internal case is out of the acrylic it worked flawlessly whenever I put it in the outer shell it just was not sensitive enough to sense my finger through the acrylic. In shame I have gone back to a regular PC switch hanging out the bottom and plan to at least make it look better but in all seriousness I will never turn this thing off (the remote control will put it to sleep and wake it up).
