How to improve my desktop video performance?

I have rebuilt(details below) eMachine W2888 running Kubuntu 9.04 that I use for email, surfing, etc. It does everything I want with one minor exception, when watching dvds or hulu streaming video on full screen the images are graining and the video becomes jerky. Small video windows on hulu, youtube, or last fm look fine and run smoothly. The system monitor say that my CPU usage is maxing out the duration of video play.

My question is what is the best, easiest, and cheapest route to improving my video quality? I'm assuming it's a hardware issue...

- I currently have 1.5G of RAM(the original 512m plus a newer 1G), I know the MB will support 2G and may max out at 4G...could adding more RAM help?

- Can/should I install a PCI video card to replace the MBs onboard video?

- Do I need to abandon my 2.8 GHz Celeron CPU and it's 478 chipset motherboard go with a newer CPU/MB combo?

- Last option would be either living with the performance as is or just buying a new system all together...



Specs;

5~6 year old eMachine W2888(rebuilt last year after the original power supply failed and took out the MB). The original Windows XP OS is currently unused on a slave HDD due to a lack of a proper repair disc and weak software skills on my part...so I'm running Kubunto 9.04 on a new HDD as work around.

- Celeron D 2.8 GHz(478)

- 1.5G RAM

- BioStar P4M900 microATX w/ S3 Chrome9 1GP video onboard video

- 22" ChiMei LCD monitor

- Kubuntu 9.04 OS.



Many thanks in advance, Mike|||Yes you should max out ram to four gigs and put PCI video card in your computer.|||if i were you i would sell that computer for a bit of money and buy a new system. i belive you can get a dell desktop for 300$ and a laptop for 350$ ( that includes shipping and tax )|||When my computer starts running slow I wipe the hard drive and start over with a fresh copy of windows. But RAM will make a big difference and make sure all your drivers are up to date.|||bump.|||Upping RAM can speed up video

Upping Video Card can support HD on hulu

Upping processor can speed up video

Pretty much, jsut upping things fix it up

Try closing background processes to lower PF usage to lower your lag when watching the videos too.

To make the video look better, watch it HD. If it lags too much, your system might be right. Need faster processor.