High memory usage with www/firefox and www/seamonkey on amd64

[Jose Luis Rodriguez Garcia <joseyluis%gmail.com@localhost>]

I am having high usage of memory with firefox and seamonkey from a
year ago (or more), with different PKG2013QX(s) (may be also
pkgsr2012QX) using NetBSD 6.1 on amd64.

The memory used (rss column) uses to be more of 2G with +50 tabs

¿Is this the usual behavior? A friend of mine with Linux/amd64 says it
takes to him 300-500 Mbytes of memory.

Now I have 130 tabs, it is using 2600 Mbytes with seamonkey pkg2013Q3
using a binary package ( I have not compiled at hand with pkgsrc).

Usually after of several days using 50 tabs or more the memory grows
more of 2600-2800 Mbytes, the system becomes unsable and I have to
restart the browser. (with 130 tabs it has grown up to the 2 GB in one
hour)

Also using a old laptop, with NetBSD 5.x i386 and old version of
seamonkey the system works a lot better that my NetBSD 6.1