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That's only true if you are using those features 100% of the time though, right ? By which I mean, there is no doubt a trade-off in play when you only use the f
by tanderson92 12y ago
That's only true if you are using those features 100% of the time though, right ? By which I mean, there is no doubt a trade-off in play when you only use the features for 15% of your workload. This is because the chip must be powered on all the time but, say, the software implementation of AES doesn't always have to be running.
- wtallis 12y agoNo, special-purpose functional units are very well power-gated on modern chips. They don't draw appreciably more power when not in use than when fused off.
- rasz_pl 12y agoyou say that, but in practice Intel is still 5-10x off ARM when it comes to idle power.
- wmf 12y agoIs that true for Merrifield/Moorefield? AFAIK they're pretty close, but only in the phone chips.
- wtallis 12y agoRegister renaming and instruction reordering and things like that can't be selectively powered down, and are very power-hungry. But if you were talking about when the entire core is suspended, then that's largely unrelated to the high-level feature set of the processor. It's about things like the analog characteristics of the transistors used: Intel builds their mainstream CPUs using circuits that can run at 4-5GHz without trouble while none of the mobile SoCs can come close regardless of exotic cooling.