depending on the server os & IIS versionyou are running, there are some hotfixes around microsoft's site for high w3wp processes... not sure if either of these fits your case, but worth a look
We don't yet have LDSD installed, but I ran into a couple of memory leaks / high cpu processes on LDMS & found that a couple of other ms hotfixes did the trick.
It should use up to 60% of the memory on the machine. It is possible to fiddle with this but I've never found it does much good. LDSD does tend to use a fair amount of memory as do many other .NET apps. It sounds as though you have the apps server running the framewok for console users as well as services? Ideally you'd have the services running elsewhere and you certanly want them to be in a separate framework to the one running console.