Other integration features such as automatic screen resizing depends on video BIOS extensions which weren't available except via specific calls in protected mode or were made possible in later driver models.Īside from the CPU halt not existing/working under VMware for NT 4.0 (Also 95), NT 4.0 SP6a with IE6.0sp1 is that oldest that still has all functionality that you can pull off with VMware. It appears hgfs requires NetBIOS functionality which in NT 4.0 and earlier could be disabled and/or removed completely, but not in later releases. The more important issue unless you're on a laptop and have heat problems with VMware and legacy Windows or DOS releases is that its integration such as hgfs (Virtual Shared Folders) depend on upstream functionality that may not be available in those releases, or has been retired for whatever reason.

DOS programs used timing loops aggressively in the early 80's, and were generally tied to the frequency of the CPU for a while the 4.77MHz variant of the 286. With Charon AXP in SMP mode, the ES40 emulator will peg 2 host cores because of the timing loop. With virtualization, some calls still must be trapped and perform manual and heavy lookups to stop-gap some SoI circuitry which is otherwise missing or inaccessible. This is a throwback to cpuidle on DOS and how the platform/architecture is emulated.

NT 4.0 tends to run with its cores maxed out on VMware.

Virtualbox vs vmware performance 2017