On: Solving Spectre and Meltdown may ultimately require a new type of processor

Never speculatively executing AVX instructions will, for bad but not uncommon cases, drop your performance by something like a factor of 10 in cases such as when you perform some AVX operation until a flag is set. I don't think there's any chance of that happening.

I said "not speculatively executing AVX-512 instructions _when the units are powered down_".