Disk cache not released

After file copy/move/read/write operations disk cache memory not released.
When i copy one 4gb file (or after 2x2gb or 4x1gb or 1024x4mb files ) disk to disk or disk to network i have full memory.
When memory is full i cant start console or another program… only reboot or hard reboot…

My system: Suse 11.0+KDE3 on 4gb RAM, Athlon 5200+, mb ASUS M3N78-EM with nvidia geforce 8300 chipset.

Maybe you have some bad memory? Have you done a memtest on your memory?

Linux doesn’t “release” cache memory, it just gets recycled for other cache or buffers or programs as needed. It shouldn’t freeze up the system to fill up memory, that’s not normal.

Memory tested - OK.