Performance in the guest OS is fine, but after returning to the already-running Mac apps, they are very slow for awhile, and the disk is very busy. Its like the app is swapping back into memory from disk... Takes way too long...
Using a Macbook 2.4 GHz with 4 GB of ram... What can I do to keep Fusion from slowing down my system? (besides setting priority to mac apps, that slows down Fusion too much) Thanks.
It's possible your guest may need more RAM. I used to run Windows XP as guest with 768 MB RAM and it worked fine at first, but after a few months I found things to be sluggish on host and guest. I set the guest to 1GB RAM and that seemed to make this much better.
Increasing guest ram will not help. While your VM is running, check in Activity Monitor under "System Memory" how your doing on memory. Mainly check the "Free" and "Inactive". Both are pretty much available memory for use. If those are very low then it might be that something else is also using a high amount of memory on your Mac.
How is the performance of your Mac applications while your VM is running?