Questiosn about XP's memory usage

[Gonad the Barbarian]

On a fresh boot, I have a tad over 65000K total listed as being used by processes in the task manager. Under the performance tab, it lists 90MB PF usage, 523760K total physical memory, 387524K available memory, and 115136K system cache. I load up UT2K4 and tack on another 150000K or so from that listed in under processes, PF usage shoots up to 460MB, Available memory drops to 50000K and then steadily climbs up to about 132000K, and system cache stays steady at about 161000K. I exit UT2K4, available memory reads as 426000K, PF usage is at 99MB, and system cache doesn't change. So my questions are:


What exactly is the system cache referring to?

Why is there any page file usage when I still have available memory?

Why am I down more available memory than the total memory being used by the processes that are running?

Where was that 80MB increase in available memory coming from while UT2K4 was running? It wasn't from that, UT2K4's footprint was steady.

Why do I have 40MB more in available memory with only a 9MB increase in PF usage after running and exiting UT2K4 as opposed to after a fresh boot?

Does WindowsXP use system memory as a hard drive cache and if so how can I limit how much is used? (in 9x the vcache setting in system.ini allowed this)

Is there anything I can do besides disabling start-up programs and services to free up some memory? I've disabled all I know to do but 136MB of memory being used plus the 90MB PF on start up seems like an awful lot.

Thanks.

 

[capeskate]

You can change the windows xp interface to look like that of windows 2000, and turn off the fading. That makes it run a little bit faster. I don't know too much about cache and page files but I would assume that xp uses both the hard drive's page file and the system's memory simutaneously. Cache'ing I think is used the same way as a buffer, just coping some place in memory, and bringing it up later so things load faster.

 

[Nothinman]

What exactly is the system cache referring to?

I believe that's the filesystem cache.

Why is there any page file usage when I still have available memory?

The number is misleading as pagefile reservations count as well so you might not have any real on-disk pagefile usage yet.

Why am I down more available memory than the total memory being used by the processes that are running?

Because of things like the filesystem cache, kernel memory, drivers, etc that don't count towards a process.

Where was that 80MB increase in available memory coming from while UT2K4 was running? It wasn't from that, UT2K4's footprint was steady.

Windows probably preemptively flushed some of the filesystem cache to disk

Why do I have 40MB more in available memory with only a 9MB increase in PF usage after running and exiting UT2K4 as opposed to after a fresh boot?

Again, things that are in the kernel that don't get accounted to a process probably got freed.

Does WindowsXP use system memory as a hard drive cache and if so how can I limit how much is used? (in 9x the vcache setting in system.ini allowed this)

I don't know off hand of a way to limit it, but generally you don't want to because free memory is wasted memory.

 

[Gonad the Barbarian]

Thanks for the replies. I've seached for as much info as I can on this and it looks like XP insists on file caching to the point where it ends up fighting with other programs that actually need the RAM. UT2K4 seems to be a prime example of this, all those textures get file cached when a level loads and essentially they end up taking twice as much memory up as they should -> they're loaded in the game's memory space and also the file cache. It makes matters worse that XP is slow to dump the file cache from RAM to make room for textures and insists on keeping a minimum amount regardless. I tried using O&O CleverCache and let me tell you it has made a world of difference. I set it to use a max of 64MB for the file cach and to enforce that limit every second and not only did it cut my UT2K4 load times in half, I can play with higher detail settings without the hitching I was getting before and I don't have to wait an eternity for my desktop to redraw when I exit - bam, it's just there. This is insane that with XP's touted memory management I need to use a 3rd party program to get the most out of my RAM. This seems it should be a major issue, a lot of people are probably spending more money on memory than they need to because of the lack off efficiency in XP's memory management.