Advanced Micro Devices Inc (AMD)

[kpf]

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Northwood was a 20-stage pipeline CPU, and Prescott is a 31-stage pipeline with a large amount of additional logic aimed at topping 5GHz clock speeds, but due to the power wall, it didn't even hit 4GHz. This was a 20% miss to expectations

Strange math, mate. Northwood was at 3,4 GHz already. Prescott was indeed supposed to reach 5GHz, it topped out at 3.8GHz.

In my book your portrayal of the miss is about off a dimension, mate: It's not a 20% miss, but a 200% miss.

But that's only half of the story. You know a deeper pipeline does help to increase frequency, but only pays off it you can scale indeed. Consequently, a 3.8GHz Prescott offers about the performance of a 3.4 performance part, well, maybe a tad more for 2MB L2-cache product, but I left out Northwood EE 3.46GHz anyway.

In essence: Prescott offers no performance increase at all, but has a power penalty over its predecessor nevertheless.

K.