Yew. 512Mb. Oddly, if you have more than that installed when you try to install 98 it complains of "insufficient memory"
There is a work around by fiddling with system.ini but all that does is fool 98 into thinking that there is only 512Mb. Is useful though if you multiboot XP as well.
If you need the workaround post back and I'll dig it out and add it.