MSN Messenger too Slow?

I'm running WINXP and MSN Messenger 6.1 on a powerful 2.66
MHZ Pentium 4. Im connected via ADSL
(http://www.adslbox.be speed test results:
- Download speed : 1747 kbit/s or 218 kbyte/s
- Upload speed : 425 kbit/s or 53 kbyte/s)
When I'm receiving others webcam images, they appear to be
very jerky.
This isn't normal as they say to me that it is better when
they are connected with other people.
I'm planning to buy a webcam myself but only if I'll be
able to generate and capture acceptable video quality.
How is this possible?
What can I expect from MSN Messenger? (Max resolution,
framerate, etc...)