How does Instruction Set Architecture (ISA) affect performance?
Same ISA means they understand the same instructions in binary. They can certainly be very different in speed. Look at e.g. the x86 family (disregard the instructions added over time). The very latest Pentium is certainly much faster than the first 386, and even within each &quot;number&quot; there are variations.
Even crasser, remember ye goode olden days of i486 and overclocking? Even the same chip can (sometimes) run at different clock rates. BTW, that is something current laptops do: To conserve battery power, the CPU runs at a lower clock rate when possible.