You will find below a quick simulation showing the benefits of Compcache's Ramzswap on Hero

Fully detailed information on the excellent opensource compache project is available here

Nov 4, 2009 - NOTE - Graphs changed (previous were flawed) Thanks goes to Jan.dk on Modaco's forums for pointing that.

After days of testing and data collecting I have found that worst compression ratio is 2.4 and best is a little over 3

First is a simulation of a worst case compression: ratio 2.4:

And a simulation of a best case compression: ratio 3:

You can do the math. For example in best compression ratio scenario, if we set max disksize at 144Mb of RAM over a total of 196Mb available on Hero, We will get between ~280MB and 290MB of RAM available to Android.
Sweet !

As of version 1.91 of the kernel, it sets a 128MB of disksize for Compcache pool which gives between ~270MB and 280MB of total RAM available to Android.