Which version of PostgreSQL are you using on your windows?
Increasing work_mem can lead to far less disk-swapping, and therefore far quicker queries. However, it can cause problems if set too high, and should be constrained taking into account max_connections. The following calculation is what is typically recommended to determine a decent work_mem value:
Total RAM * 0.25 / max_connections
If there are large reporting queries that run on the database which require more work memory than a typical connection,work_mem can be set for those particular queries. If, for example, there is a reporting user that only runs infrequent but large reports, a specific work_mem setting can be applied to that particular role.
e.g.
ALTER ROLE reporting SET work_mem = '64MB';