On 08/09/2012 04:07 PM, Sampsa Laine wrote: Why is SIMH so slow though? Because it's extremely portable with no architecture-specific assembler assists. As I won't use anything that's NOT portable, I consider it to be screaming fast. As far as I can understand, one MIPS is roughly one VUPS, correct? More or less...depends on who you ask. So how come I get 14 VUPS on the same host running SIMH whilst my Hercules install peaks at 180? Ummm...because one is an IBM mainframe architecture and the other is a VAX? MIPS is a very, very different thing between different architectures. Are the architectures that different (obviously they are) or what is it? They very much are, yes. -Dave -- Dave McGuire, AK4HZ New Kensington, PA