Recently installed Ubuntu 10.04 on an old Dell Dimension 4600 with Nvidia FX 5200 video card using 173 drivers. All appeared to work well except for flash video stutter both Firefox and Google Chrome (not Chromium). Somewhere I read something about there being a difference between installing the flashplugin directly from Synaptic and using the item called flashplugin-installer in Synaptic.

After installing flashplugin-installer, the stuttering videos are fixed.

Apparently, adobe-flashplugin installs a different driver than the one installed by flashplugin-installer.