Thanks all for answers. Yes, I have some updaters and antivirus running all the time, but they they still take less than 1/4 of my total memory. Except web browser, antivirus is biggest resource hog, but I'd say that it's still fast compared to competition. There are no hidden background scans, I have configured it in such a way, that every action is on demand. System is configured properly, indexing is disable and prefetcher is on. Paging file is managed by windows and is in 1 fragment. It might be disk thrashing actually, I am not really sure, but for example system using 300 MB's of memory is also using 500 MB's of page file, while I have 1 GB. Hard disk is pretty old, but never had any bad sectors and it's being constantly checked and defragmented. I am still analyzing system with various tools, I'll post results later. Btw, just to clarify - I don't use any memory managers, I have tested how they work and in fact I want something completely opposite.