Be sure to make backups of all files before changing anything. There is something peculiar about windows' memory management. The more memory you install, the more windows uses. Not for speeding up your software mind you, but for caching its disk cache. More logical would be the other way.
More memory means less disk caching, means less memory cache needed for the disk cache.
Here again a simple solution. This will limit the memory cache size to 4 megabytes max, keeping the rest free for software. This will mean a lot less disk activity. It may be worthwile to set minimum and maximum to the same amount, thus preventing resizing of the buffer. CacheMan do this for you.