How do I increase illustrator's resorces?

Question

Hi, I'm using illustrator CS5. my system specs are:
windows 7 x64
4gb ram
intel i5 chip
Ati HD570 graphics
1tb Hard drive - for system, progs and files
35gb hard drive acting as dedicated scratch disk for illustrator/photoshop
The trouble is that I'm pushing illustrator to it's limits and it's struggling, sometimes crashing.
I've got a desktop gadget that measures my CPU and RAM usage. while illustrator's struggling, the RAM usage goes up to about 75% tops and the CPU is at about 25%.
is there a way to allow illustrator to use more of my resorces? can't find it in preferances.
cheers!

Answer 1

ok, here's an interesting update. I bought some new ram, stuck it in and did a little test:
the old RAM was 4gb of matching ocz gold C8 sticks and I replaced them, in the same dual channel slots, with 8gb matching corsair vengence C8 sticks. The RAM has been tested with memtest for errors and there's none.
With the old 4gb RAM, I loaded up a file in illustrator and gave it some hard work to do. In windows task manager I took note of how much ram and cpu was being used by illustrator. I did the same test 3 times in exactly the same way, restarting illustrator after each test. Each time it had practially the same result: the cpu usage stayed at about 25%. the memory usage for illustrator crept slowly up (over the period of about a minute) until it reached about 1725,000 k and then illustrator stopped it's work and reported "Can't finish previewing: There isn't enough memory." (total RAM used for the entire system during testing was 71%)
with the new 8gb ram, I performed the same tests 3 times with the same file in the same way. This time, illustrator's CPU usage was about 25% and it's memory usage crept slowly up (over the course of about a minute) until it reached 1730,000 k and then illustrator reported the same "Can't finish previewing: There isn't enough memory." on the first 2 tests. on the 3rd test, illustrator froze up completely. (total RAM used for the entire system during testing was 37%)
next I tried the same tests but with the old and the new ram installed, so now I've got 12gb quality C8 ram. The results: CPU 25%, memory about 1718,000 k - same "Can't finish previewing: There isn't enough memory." message. (total RAM used for the entire system during testing was 26%)
Conclusion: so there you have it - either my pc/illustrator is not set up right or illustrator can't use more than about 1730,000 k of memory.