Not an EE or chip designer but 1. stack based arithmetic requires a stack (duh) whereas registers are more general use. Put another way, a stack is specificall

Not an EE or chip designer but 1. stack based arithmetic requires a stack (duh) whereas registers are more general use. Put another way, a stack is specifically for arithmetic whereas registers can be used how you like. 2. More importantly I suspect a stack implementation puts extra pressure on the register set (edit: NOT the register set, sorry, I meant those locations/hardware used for the stack) - read item 1 and item 2 then push the result back onto where item 2 was. With registers you can put the result into any other register, which allows other instructions to execute, not stall waiting for the result to appear on the stack. 3. A stack is a bottleneck, you can have multiple ALU units wich allows multiple instructions to happen OOO when you have registers. Try doing that with a stack (see 2 again) happy to be corrected