HINT: Parallels memory configuration

A saw a number of problems with VM memory configuration in this foum, - and there are some things that need to be clarified.

There are 2 config values that should be taken in consideration while configuring your virtual environment:

1) OVERALL memory for all VM's running in your system (Properties->Memory)
2) VM MEMORY size option

Generic recomendation is that OVERAL > VM MEMORY + 10%

Let's say, you are running 2 VMs with 256MB guest memory each, than OVERALL memory option should be at least 600 MB.

t is very important to let Parallels use at least +10% of guest memory for it's needs with OVERALL memory option, cause otherwise it may become really slow because of hard-disk access.

 

On the MBP with 2 GB memory Parallels default was 1 GB over and I upped xp memory from 256 to 512. I decided to try lowering xp memory to 256. I count the number of 3 block passes under the windows logo. With 512 memory Beta 3, it was taking 9 crosses of the blocks on the first launch after starting Parallels Workstation, and six on the second and then five there after. With 512 of memory it takes 6 crosser, 3 and 2.5 there after. I dropped the total memory to 800 Mb and could not see any difference. Is there any reason to not leave total memory on the default of maximum?
256 for xp does not seem to slow applications but I have not tested much

 

It makes sence mostly when you are running some memory-consuming applications in your Primary OS - and you want to make sure that Parallels will not use too many memory. Anyway, Parallels will not use more physical memory then guest memory + ~10%.