MORE RAM is always the correct answer but a lot of people over look or don't know about the graphic/In game options you can turn down to save RAM
Some of these were covered in the linked guide but this is the definitive short list.
One thing totally wrong about that guide though - NEVER - Duplicate Everquest Folder / Hard Drive Usage This is WRONG.
Game Options
1 Open the normal EQ Launcher like when you patch
2 Click advanced tools, 2 little gears in the lower let hand corner.
3 Click Game Configuration from the window
4 Select the video card you play the game on. you may mutiple if you have a multi screen setup Click Next
5 Deselect any models you don't need to see the Luclin models to play. I always leave horses and elementals or they don't work right Click Next
6 Uncheck Social Animations, Mip mapping and Dynamic Lighting. sound if you can handle playing without it
7 Make sure texture compression and texture caching is checked
8 Set Texture Quality to low
9 Click Finish
This can save save 100's of megabytes of ram over multiple instances.
In Game
Alt O to open options
Click on the display tab
Slide your clip plane to 75% on all toons
Change Sky Type to simple
TURN PARTICLES OFF ON EVERY TOON ON EVERY TAB - Spell, Env, Player
Click Advanced button
Uncheck everything below Allow 1.4 pixel shaders - Allow 2.0 pixel shaders, Use adv lighting, radial flora etc,
Terrain Texture Quality select low
Memory mode Balanced
Dynamic Sky reflection Tiny (32)
Max frames per second 40
Use the following command on all toons to make sure your logging is off
These are the original OLD SCHOOL tricks before we had the insane computers we have today. You will be amazed at the performance boost these settings can have