MeGUI profile / list of x264 settings for slow target PC ?

Hi, what MeGUI x264 profile, or settings to use, if I want to target X264 encoding for slower PCs of my friends ? So encoding speed does not matter (much), but decoding speed can be critical. Also, what is supposed minimal HW configuraion to play H264 encoded PAL TV 720*576 (without DXVA) ?

Note that I keep PAL resolution 720x576, using usually 1pass CRF Q26, resulting typically 600-750kb/s ( 400-500 MB for movie )

Those kinds of concerns are why I tend to rely on insane profiles - mainly because they can keep the bitrate down very easily, even if they take forever to encode. It's not a panacea for decoding ability, though. But if you can manage to keep the bitrate contained, even using the advanced features of H.264 can work well on old setups. Basically I noticed that Advanced Features + High Bitrate = Decoding Nightmare, but Advanced Features + Low Bitrate (possibly due to said features) = Generally OK. The type of content makes a huge difference here - if there's a lot of noise or heavy motion, then the bitrate will spike and cause problems, while mostly static scenes will be relatively okay on playback. For some of the stuff I have that's encoded at 23.976fps or 29.97fps using insane settings, my computer (which has a Celeron 2/Pentium 3 Coppermine, 1GHz, 256 MB RAM, 100 MHz FSB) can decode at roughly 19fps or so using libavcodec. So for some videos a lag is more noticeable than in others. This is just at 480p, though, and I generally encode with CRF 18. Of course, it is also true that not using some features, notoriously CABAC, will raise the maximum bitrate that the video can be encoded with and still be playable on an older setup. It ultimately comes down to how efficient you want compression to be.