The ISA Server Web Proxy Service uses a RAM cache to insure that requests for cached objets are answered as quickly as possible. However, if you notice that the W3PROXY.EXE process is using more RAM than you're comfortable with, you can change the percentage of Free RAM in the Advanced Properties of the Web Cache configuration.
Keep in mind that the Web Cache is not using a fixed amount of RAM, just a percentage of free RAM. Therefore, ISA Server will release RAM as required by other applications and services that require it.
RE: Change the Amount of RAM used by the Web Proxy Cache - 30.Dec.2002 9:20:00 PM
It's correct that ISA should release the RAM for use by other apps. But I found that if you leave the default, 50% of RAM for Cache, and have a large number of users, it will cause the web proxy service to crash, ultimately resulting in no internet access for your users. Microsoft recomended I set this to 20%.
From: South Africa
I have 11 ISA Satellite servers which have a 80-100 users. I to have set these servers to use 80% of available memory. The 2x Enterprise ISA servers which have 4000 users and are load balancing are also set-up to 80%of available memory. I attended the MS ISA course and they have recommended to increase memory allocation between 70-80% to have MAX caching preformances