Hi Rob and thanks for your support
Initially I also gave a look on Ivor snapshot but it was not compiling with the X tree I had at that time. This does not mean that the solution is not good, because in the very beginning I had several problems in compiling anything on this box ... Now it may be worth a new try ...
In general all of the different alternatives I've found are related to Xorg or to "cutting edge" Xfree86 releases, that is a bit far from keeping the things close to Pluto path.
One of the approach I had (maybe a bit extreme ...) was to build my box from scratch with debian kernel 2.6.12 EPIA patched and DRI enabled, replace Xfree86 with Xorg EPIA patched and compile X driver. Then my idea was to install Pluto on top of it, with all sources in order to be able to rebuild all needed modules. Unfortunately it came out in the end that Pluto installation wizard does not support anymore custom installations like this .... so pity because the box was working like a charm with Xine ...
So I had to revert to a more standard approach, and this is why I'm making now some more conservative choices (of course besides to a bit of lack of overall knowledge of linux and Pluto..).
Basically I don't know what kind of impact may have against the Pluto system the choice to replace Xfree86 with Xorg, or simply upgrade Xfree86 to a 4.5.x release (4.5.x has native VIA EPIA support, currently Pluto uses a 4.3.x that has to be patched). Any suggestion/comment on this topic is greatly appreciated, I wouldn't mind to save some time on potentially unuseful tests
What I can surely say is that all these performance problems would instantly disappear the minute Pluto guys feel it's ok to drop xine and use vlc instead.
I made a simple test, i.e on a standard Pluto install (no xfree hack nor xine upgrade) I killed all Pluto stuff and tested manually vlc and xine playing the same divx file (one after the other, not at the same time).
Well... vlc has WAY better performances even with standard xfree drivers, it never looses a frame and overall playback is fluent and audio/video are always in sync.
To get the same behaviour with xine I have to use a patched xfree86 server/driver and xine 1.1.0, but nevertheless it uses more CPU.
I know that vlc has some stability issues, so all we have to do is to wait and find a good compromise with xine in the mean time.
As an update on what I'm testing now, I managed to recompile/install xine 1.1.0 over 1.0.2 release, and things are "almost" working.
"Almost" means that xine does not loose frames nor get out ov a/v sync anymore but sometimes it refuses to play some files, and I have to wait some time and retry.
I didn't figure out yet what it is, I'll have to go deep with the logs.