After untarring large archive....

My system seems to slow drag really bad just after untarring a large archive.
It seems that the directory database needs to be updated just after the
untarring of the archive - this is a guess - maybe it is an ext 2 filesystem
problem. I have been plagued with this for many years, and I am sure that I
am not alone. Is there some way to eliminate this problem?

Using:
Slack 8.1 (But, it was always a problem on any distro that I have used).
400 MHZ w/ 384MB RAM

Thx in advance.