98 will run on a dual-core CPU.  The 98 kernel was not written with
multi-processor operation in mind so it will not perform the necessary
housekeeping and organization to activate both cores and allocate
processes to them.  So 98 running on a dual-core will only use 1 of
the cores.

The Intel Celeron D 365 (3.6 Ghz) is probably the fastest single-core
CPU that will ever be available from Intel, and I doubt that any
core-2 cpu would run Win-98 faster than the D-365.

Intel has some Core-Solo's, but I've never seen them available for
retail sale, and their clock speed has never been higher than 2 ghz as
far as I know.

Hi Chris,

   The problem is that you can run Windows 98 SE with a Dual Core
Processor. The only problem is that you need to Limit the amount of Physical
Memory you run in that computer to 1 GB otherwise, you won't be able to boot
into Safe Mode if you have 2 GB of Physical Memory installed.

   I am in the middle of doing this exact same thing.

   I purchased a Mach Speed P4MSD-800D2 Motherboard with an Intel Pentium D
2.80 Ghz processor and one stick of 1 GB of ram almost at the same time. I
did not have problems until I added a second stick of 1 GB of Ram about 30
days later.

   You need to reinstall Windows 98 SE from scratch, otherwise it will not
work or run correctly. Start out with 1 GB installed. After Windows is
loaded and you can boot into the operating system, boot into Safe mode and
go to the Advanced Menu of msconfig and Limit the amount of memory to a
single figure of say 512 MB.

   Now shutdown the computer add the second stick of 1 GB if you go that
route. Restart the computer and go into Safe Mode, you can't. Reboot the
computer and restart Windows 98 SE and you can boot into Windows 98 SE.

   If the motherboard has SATA Controllers, you must disable them, because
Windows 98 SE can't handle them. Just the one going to a DVD Drive. Leave
the one to the Hard Drive Enable if it works.

   The computer I am working with, I am triple-booting into Windows 98 SE,
Windows ME and Windows XP Home Edition Service Pack 2 on FAT32 File System.