Advanced Micro Devices Inc (AMD)

[HailMary]

This was my point-- how significant is the actual increase? Less than the ratio of 20 to 31 would imply? How much less? That's all.

Hard to say, and it varies by code.

What is more important is how much logic was reduced per stage going from 20 to 31. This would tell us the frequency headroom. The number of pipeline stages increased by 55%. Each stage would have a fixed overhead for clocking, so they give up some of the 55% there. A 31 stage pipeline is more complex than a 20 stage pipeline, so they give up some there by needing more logic. The die size grew (if measured on the same process), so they have longer routes going between various logic, possibly meaning longer critical paths. Lastly they may not have been able to balance the previous 20 stages of logic into 31 stages perfectly, which could give up some or all of the 55% depending on how bad the imbalance is.

We can see the result - Prescott is slower in frequency. Thinking about it more, low Prescott frequency is doubly perplexing. I would not have even expected this poor of result if Prescott came out on 130nm.

I wonder how high Northwood would clock on the 90nm process? Probably over 4Ghz easily. Makes me wonder why they didn't just extend Northwood's life by doing a shrink to 90nm as a backup plan to Prescott.

I feel like I'm looking through a fogged up window trying to understand what is going on. It could be they can fix the problems fairly quickly, and suddenly Prescott will jump to life, and it could also be that it would require major rework to fix. The first case is scary to me as an AMD investor, as it implies a wounded predator ready to pounce once it stops bleeding. There may be little warning.