Well, the decode used to use 15% of an x86 core's power budget but it hasn't grown as fast as the other structures so I'd guess more like 10% these days. So yo

Well, the decode used to use 15% of an x86 core's power budget but it hasn't grown as fast as the other structures so I'd guess more like 10% these days. So you're losing out on being able to turn off a small but noticeable part of your active power usage. But on the other hand fewer instructions executing means less active power draw in the rest of your core too. So it's not clear which way it goes in terms of Watts, but certainly you use more Jules.