SQL2000 Max memory used now what

I have an older Dell boxen with 2000 SVR SP4 with SQL 2000 SP4
Our app is getting slower as it ages and the mainboard cannot take more than 1GIG of ram.
Without getting new hardware, Id like to use this time to tune the DB before we spend $$ on an upgrade.
When I let memory go dynamic, it eats into all our swap and crawls
If I strap it down to 512MB, it speeds up for a while then gets slower, but not as slow as above (IE no swap pressure)
I have used Tuning Wizard, Update Statistics, Profiler and Perfmon and Process Explorer traces for baselines.
Some Profiler traces show some SPs taking 45-90 seconds to return result sets (bad app)
Target Memory hovers at 500MB-550MB and Total starts at 100MB goes up to 500MB by the end of the day
But since the app is commercial, its hard to change the front end,
Although I have SA on the box to eval the backend SPs, Views and other.
Ive used this to create my own SPs for Crystal reports.
Box is a Dual PIII-800 with a Gig of ECC and 3 18GB SCSI-180s off an older Dell Megaraid RAID in a PCI slot.
Seems like a good learning platform for sub-molecular evaluation...(tuning class)

2000 STD

Sounds like your stuck between a rock and a hard place. Like trying to defrag a HD at 100% full. The good news is if you get a decently new mobo/cpu, you can get 2x2GB pc667 ecc kingston or crucial memory for ~$120 from newegg. Pretty darn cheap.
GL

yeah i know.
Dell mobo actually maxes at 4x512 PC133 ECC for 2 gigs total for $600 from Crucial
I think I need to watch profiler traces and indexes
wondering if adding more disks to raid5 willl help
these 80-pin 18GBs are only $50, I could put 12 in for $600
Joe Chang always has 10+ disks...

those links are developer stuff
i dont have access to the source client, so i cant control SELECT * etc
But I can take baselines.
What happens when you host a multi-gigabyte DB on a 4GB STD box, switch to ENT?