I have finally given in and got myself an Asus eee 901 netbook. So now I have tried pianobooster on my iMac G5 and the netbook with both WinXP and eeebuntu:
iMac G5 2 GHz: despite being a fairly old processor, the setup works beautifully, is very easy to setup and there is absolutely no midi lag nor any flickering in the openGL window
Asus eee 901 1.6GHz Atom processor and WinXP: easy to setup (windows comes with a softsynth preinstalled) but there is a heavy lag which makes the whole thing rather pointless
Asus eee 901 with eeebuntu 3.0: requires installation of jackd and fluidsynth, which is rather easy via synaptic. Then one has to start jack via the appropriate control panel followed by qsynth. There are a few problems here:
1) use of RT kernel requires a bit of tinkering
2) both jack and qsynth/fluidsynth require a bit of fine tuning (buffer size, sampling frequency, sound font etc.)
3) piano booster does not like compiz, so this has to be turned off
in the end, even after playing with the settings for a while i was unable to reduce the lag much more than what I was experiencing with XP.
The conclusion seems to be (as already suggested by Louis on a different post) that on a netbook the only viable solution is the use of an external sound module.
I have finally found a solution to this problem when using Ubuntu 9.04 and Intel graphics chips found in netbooks and laptops. The problem was caused by the Intel Drivers on Ubuntu 9.04 which were MUCH worse than on Ubuntu 8.10 which I had. (My net book mouse button failed so I got a replacement under warranty and then found PianoBooster does not work with Ubuntu 9.04 and Intel graphics chips). The solution i used is to upgrade to Ubuntu 9.10 and with the latest PianoBooster source code from svn. I have just added in a fix for this problem.
To get the latest code from svn type the following from the command line.