5749999990-1010000000=4739999990*10(ten being the number of digits in each number)=47399999900/3/1024/1024=15068 megabytes. Trouble with 32 bit apps you can only address 2 gigs memory so lets work with a 1.5 gig addressable beyond the application overhead. As you can see only about 10% can inhabit active memory, that isnt too bad a cache percentage. Optimizing the cache itsef would be the trick and as an off the shelf kind of guy I would use someone elses, not build my own.
thanx,
bill