Hello,
I had the same experience after a clean install of MDK 10CE with a similar system until I updated it. Now it is much better with only occasional lock ups. To update your system do the following:
-Launch Software Media Manager
-Click add
-In the Add a medium window click on Security updates
-Enter
ftp://ftp.proxad.net/pub/Distributio.../Mandrake/RPMS in the URL: entry window
-Click OK
-Click on update_source in the Configure media window
-Click update and allow it to retrieve the updates for your install(this may take a while depending on your connection speed, and it may crash but keep trying until you succeed)
-After it is done go to Mandrake Update and click OK when it asks to update
-Select the packages you want to update or select all if you want to update everything(the latter is probably best)
-Click install and wait for packages to download and install
*Note that the mirror I gave here is not the only server available and may not be the best for you, check the mandrake download site for mirrors that may be better for you. Look under mirrors of the i586 not the ISO's.
Good luck.