Hi,

I've noticed that disc caches get inefficient when used for longer time. I see this when I compile my project (~1000 cpp
 files, build folders with all the compiled objects and binaries > 2.6 Gb). If I build right after computer reboot the 
build completes much faster. However if computer had been used for some time the build can take twice as long and even 
more.
Having experimented a little I've found that the main bottleneck is the includes search/loading during compilation. 
Nothing helped except for increasing disk caches size. Currently my system runs with "blk cache=1792m,mfu=33,vnode=10240
" on 4Gb RAM quad-core machine. If files are compiled soon after reboot the disc activity heared is minimal. However if 
project is built after some use (even if build folder with project files and compiled objects are just deleted and 
unpacked once again) the disc activity on next build gets much higher for each file and pauses between files get 
noticeably longer.
So something is definitelty wrong with disc caching algorithms you implemented for 650.