win 98se cant utilize more then 512 in system ram , unless you install the offshore 1.5 service pack ... and even with that it doesnt always work properly .
i would lower the ram back down to 512 and since your running a 256 mb video card i would load the textures into that.
in the ah settings folder is a video8.cfg thats the file you deleate when you need to try a different settings at the start of ah .