ubuntu 9.04 flash 10. firefox 3.0.10 too slow in fullscreen mode ?

What version of Ubuntu are you using? 32 or 64bit? What video card and processor do you have?

 here is a partial output from lshw. the volume control for the sound system is not working either. if i click on volume control and try to adjust the sound using the slider bar or mute it it doesn't work. i have sound now. i appreciated any help on this.

ubuntu 9.04
flash 10.0.r22

 firefox 3.0.10 too slow in fullscreen mode ?

 product: Intel(R) Pentium(R) 4 CPU 1.60GHz

Display UNCLAIMED
                description: VGA compatible controller
                product: Rage 128 Pro Ultra TF
                vendor: ATI Technologies Inc

multimedia
             description: Multimedia audio controller
             product: 82801BA/BAM AC'97 Audio Controller
             vendor: Intel Corporation

 multimedia
             description: Multimedia audio controller
             product: 82801BA/BAM AC'97 Audio Controller
             vendor: Intel Corporation

it is 32 bit

I would say the culprit here is the flash plugin, as it is poorly optimized and puts a heavy load on the CPU, so in your case you probably won't be able to play flash in full screen.

I tested this on a P4 equipped laptop, when in "low power" mode (1.8GHz) the CPU usage while surfing a flash site or watching a video is close to 100%, and depending on the site or video, it will drop a lot of frames and slow down Firefox to a crawl. When in "normal" mode (2.8GHz) cpu usage is still high, but not 100%, so flash sites are bearable. The older flash plugin 9 was even worse.

The 64bit flash player is a lot better performance-wise, but is far from being called "optimized". You're out of luck here, as the Pentium 4 processor has no 64bit support.

As for the sound, it is probably related to pulseaudio. I cannot help you here, I use Kubuntu, which does not use pulseaudio.

I am with the manufacturer of The Wave at CatchTheWaveTV.com (a PC/set-top box that is designed to connect to TV's). We did a software build last week on 10.04 and also found it was much slower for video streaming than 9.10 (Firefox/Flash, in standard small/standard-size windows on websites), and therefore unacceptable, so we must stay with 9.10. 10.04 is almost twice as jerky visually - corresponding to load factors in the system monitor of 2.4-3.5 vs 1.5-2.2. Also, a minor aggravation, but long titles for desktop icons do not wrap into two lines.
The Wave uses the Intel Atom N270, and it does smooth video in the small/standard-size windows (also, we will be introducing a Wave FS that will do smooth full-screen video, and a Wave HD that will stream HD).

I am with the manufacturer of The Wave at CatchTheWaveTV.com (a PC/set-top box that is designed to connect to TV's). We did a software build last week on 10.04 and also found it was much slower for video streaming than 9.10 (Firefox/Flash, in standard small/standard-size windows on websites), and therefore unacceptable, so we must stay with 9.10. 10.04 is almost twice as jerky visually - corresponding to load factors in the system monitor of 2.4-3.5 vs 1.5-2.2. Also, a minor aggravation, but long titles for desktop icons do not wrap into two lines.
The Wave uses the Intel Atom N270, and it does smooth video in the small/standard-size windows (also, we will be introducing a Wave FS that will do smooth full-screen video, and a Wave HD that will stream HD).