|You might check this old thread:|
The link in my # 3 there is some screenshots of modifications to 98 to allow large amounts of ram. Also check Whitphil's comments about the cache file settings.
The link is to driverguide and they're so screwed up now I wouldn't recommend downloading it from there. If you want it send me a private message with your email and I'll send it to you.
But as mentioned previously, the ram is probably not what's slowing it down. You got 98 on a SATA drive? How did you do that?
Also, to get 98 to run right you'll need 98 drivers for all the hardware. Many of those drivers probably don't exist. I think you'll eventually find that it will be much easier to install 98 as a VM within XP or find an old P-III or something similar and install 98 on it.