> By not warming up they refer to instances when early performance is higher than later performance or when the performance doesn't settle. which are both case

> By not warming up they refer to instances when early performance is higher than later performance or when the performance doesn't settle. which are both cases where you would be disappointed were you to use the VM as a server. I think their point is that VMs are more unpredictable than many realize and also intrinsically unpredictable in some cases.