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SanAndreasEleva
Enthusiast
Enthusiast

How do I mask out VME on AMD Ryzen 7 1700 for Windows 16-bit/32-bit hybrid VMs (Windows 98)?

Since my last discussion last month I've conducted some research regarding Ryzen and 16-bit/32-bit VMs, and apparently there seems to be a bug involving VME (Virtual-8086 Mode Enhancements). The INT instruction apparently misbehaves in V86 mode with VME enabled. More details are explained in the article below.

VME Broken on AMD Ryzen | OS/2 Museum

So then I realized, even though it is never mentioned, that not only Windows 98 (which is what I'm having problems installing) is effected but possibly any 16-bit (DOS/Windows 3.1) or 16-bit/32-bit hybrid (Windows 9x) operating system is effected (the article may state that 32-biy OS's are effected but I do have a Windows XP VM myself, it installed fine and it runs fine on Ryzen). The article states that people are having problems running 16-bit applications in DOS boxes in Windows VMs, especially in Windows XP (but I don't intend on running any 16-bit applications on my Windows XP VM).

So the article states the workaround is masking VME, but I would like to know what the precise string is to paste into the VM config file to test on the Windows 98 VM to see if masking out VME fixes my installation problem just so I know I'm posting the string of code correctly because I've mentioned before I have limited knowledge in CPUs. Thanks.

21 Replies
bonnie201110141
VMware Employee
VMware Employee

We also ran into the same issue when installing Windows 98 in AMD Ryzen 7 1700 host. And we also found that the same issue occurs in a KVM virtual machine. So it does not look like a bug in VMware Workstation. Currently we found that with ESX 6.5 with CPU=HV or BT & MMU=SW, Win98 can install very well. We are trying to investigate if there is some reasonable workaround with Workstation, but no solutions are found yet.

an65001
Contributor
Contributor

What are some recommendations for "masking" an AMD Ryzen 7 1700 Eight-Core CPU for a Windows 98 vm?

I've mentioned a fix for Windows 98 on this forum post. It involves disabling the 32-bit disk drivers.

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