It isn't too little it is normal, the ashDisp.exe is only the avast icon and interface to the on-access providers and other avast options, simple user interface, program settings, etc. So I wouldn't expect it to be using much memory. Mine is currently at 2,676KB but I have been using it a lot this morning, it really is nothing to get concerned about (Firefox is currently consuming 54,900KB and my firewall 30,328, Explorer 39,902KB). It also depends on when you check the memory use and what you monitor it with.
The windows task manager isn't very good in that most people look at the Memory Usage and that can be wildly out, Vlk or Igor I thing suggest viewing the VM Size figure. Even then what you really should look at is how your system performs and not how much or little memory is being used, that is what memory is for and why you bought it by the Giga Byte
The main work horses of avast are the ashServ.exe and ashWebSv.exe and these use the lions share of the memory used, the more active they are the more memory consumed, but it gets handed back as the activity subsides.
