Well this is not official word, but I can throw out some knowledge based on experience. I only run 2gb of ram in my master backend, so you should be good with 2gb in a frontend only setup, even with onboard video. I went with 4gb and it looks like I dedicated 1gb to video through the BIOS. With VDPAU you want at least 512mb of video memory, so 2gb should leave you plenty to spare.
As far as running a Backend from this, you could most likely get away with it, especially with something like a HDHR. However, I wouldn't recommend it, the atom processor just isn't going to be powerful enough for commflagging and other backend tasks. As a secondary backend, now that might work.
Re: peak memory use as mythtv frontend?
Well this is not official word, but I can throw out some knowledge based on experience. I only run 2gb of ram in my master backend, so you should be good with 2gb in a frontend only setup, even with onboard video. I went with 4gb and it looks like I dedicated 1gb to video through the BIOS. With VDPAU you want at least 512mb of video memory, so 2gb should leave you plenty to spare.
As far as running a Backend from this, you could most likely get away with it, especially with something like a HDHR. However, I wouldn't recommend it, the atom processor just isn't going to be powerful enough for commflagging and other backend tasks. As a secondary backend, now that might work.