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I was wondering if anyone else experienced this issue and has knowledge on how to fix it. I am running an AMD Phenom 9850 Quadcore under Ubuntu Lucid 10.04.

Problem: Running my old Windows 98 SE in virtualbox and CPU Frequency left alone at "On Demand", when Windows 98 SE begins to reach desktop, my CPU would spike up one core and beep, then shut down my whole system (Native), not just the virtual machine. All other windows XP and above runs just fine without a problem. I gave Windows 98 SE Virtual machine 512MB ram, tried with 2d and 3d hardware acceleration both enabled and disabled.

Work Around: My only work around now is to force my CPU frequency to run at 1.25Ghz (all 4 cores because don't know which one will spike at random) from the Native Ubuntu Lucid CPU Frequency monitor.

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up vote 2 down vote accepted

This problem occurs because MSDOS-based systems, including Windows 3.x, 95, and 98 do not send the proper idle instruction to the CPU when they are idle. Instead of sending the CPU a "HLT" (halt) instruction, which puts the CPU idle until needed, these operating systems will instead loop through code that does nothing, but keeps the CPU busy.

How to fix (source, by fixedwheel):

Install rain, waterfall or cpuidle in the Win9x guest - my preference is rain as it only does what is needed -replace the idle loop with HLT execution- and nothing more

here is a link explaining something about, related to real hardware [][2]

d/l rain from here: [][3]

I checked, and the download link for rain does not seem to work right now, but you should be able to use one of the other programs mentioned or find an alternate download source. Just get one of those programs and install it in the virtual machine.

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Will give it a shot tomorrow with time. thanks. never saw this one, only for the video driver. – robx Jun 6 '11 at 4:59
This unfortunately did nothing to help. Even after installing rain20 in the GUEST OS and made sure it's running, putting my CPU Frequency back to "On Demand", one of my core would spike up and shut down everything. Perhaps it's outdated. – robx Jun 6 '11 at 15:37
Try one of the others listed. Rain is a good one, but it's incompatible with some AMD processors. Phenom might be one it doesn't get along with. – TuxRug Jun 7 '11 at 4:01
I think I will just stick to throttling the CPU Freq at 1.25GHz while running win98. I'm reluctant to keep trying and having my machine abruptly shutdown with risk of damaging something in Native OS. – robx Jun 7 '11 at 4:32

This does not happen with Win98 installed in acpi mode. See this Tutorial.

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