I’m not totally sure these days, but it’s been said a lot that even users choose the same VPS plan, the server CPU may be different. What developers often do is to keep creating a server until they get the best out there.
How do you prevent this difference of servers upon generating a new client server through WPMUDEV? For example, Linode has dedicated CPU plan which should perform generally better than standard plans, but so far WPMUDEV hosting plans are based on standard servers considering the prices.