I am trying to get windows 8 release preview installed on an old rig which is a p4 2.66 ghz 1gb ram 200gb hdd and geforce fx5500 video. however windows 8 setup (small program you download from ms) says the processor is not compatible with windows 8. Did they jack up the requirements further than whats on their site or what is happening here?
Coming from someone who has a P4 and did want to put the RP on it. There are some P4's that would work just fine with the RP and RTM despite what everyone here says. While MS was deciding on whether to enforce having the NX bit (No execute, many names for it..), they polled the telemetry they had on Windows usage and found that only 0.1% of users would lose the ability to run Windows if they enforced hardware NX support. Up until now Windows has always required NX since around the XP SP2 timeframe, its just that MS added software emulation for NX, even up until the Win8 CP. Since they felt that percentage was low enough they went ahead with it. If you dont know, NX support deals with bringing malware protection to the processor. With some of the new features MS has added to Win8 it utilizes what NX gives to the computer.
There is nothing you can do about getting the RP to work with your existing processor but there are newer P4s that came out in 2004, 2005, and 2006 that do have NX support and they are cheap, under $20, if you don't mind refurbished versions. Depending on your chipset on your motherboard and the version of BIOS you have. If your chipset/BIOS supports the 2006 chips then there are some that are still completely new P4s that you can buy, but they are more expensive around $40-$50. You wouldn't need to buy anything else to make that newer P4 work with your computer. The same RAM, video card, etc everything would still work.
Also despite what others have said here your FX5500 would be fine as you have probably noticed with the CP. Even though the last driver that was released for it was right when Windows Vista RTMed. If you don't have a board that supports PCI Express there are some newer GPUs that are PCI just like your 5500 and are still supported by drivers and probably will be for while longer. The Geforce 9400GT, its not really expensive compared to GPUs today and it would be a big upgrade from your 5500. I personally also upgraded from a FX5200 to this 9400GT.
Hope any of that helps!