Simply put.
We wouldn't notice anything.
Our perception of the world would be based only on the compute cycles and not on any external time-frame.
The machine could run at a Million Billion hertz or at one clock-cycle per century and your perception of time inside the machine would be the same.
Same with low ram, we would have no indication if we were constantly being paged out to a hard drive and written back to ram as required.
Greg Egan gave a great explanation of this in the opening chapter of his Novel Permutation City