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Technology Stocks : Advanced Micro Devices - Moderated (AMD)
AMD 214.990.0%Dec 26 9:30 AM EST
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To: jcholewa who wrote (5462)8/17/2000 5:32:13 PM
From: kapkan4uRead Replies (1) of 275872
 
<> Besides the difficult datapath issues associated with the double speed ALU, the control logic is likely rather complex.
> Removing the double speed ALU would probably be a 6-12 month effort.
> Intel does full custom design, and any change like that is a major hassle. One of the big advantages that AMD has is they
> use a cell based datapath methodology, which allows for much faster design turnaround times.

Okay. I'll erase thoughts of dissolving FCLKs from my head, then. :)>

I don't see where 6-12 months effort estimate is coming from. Double speed ALUs can also run single speed without any changes. P4 already has temperature control circuit that throttles the clock down when it is about to fry itself. The changes to the corresponding pipeline stages should be minor.

The problem of removing double pumping is on the PR side. What would be the official chip frequency? They have three frequency domains now:
1. L2/decode half frequency
2. Trace/L1 fetch/execute full frequency
3. ALUs double frequency

Today they can argue that the full frequency is a fair/average definition of the overall frequency, even though there are much more transistors in L2/decode than in the ALUs. If they remove double pumping then they will have to quote a 3/4 frequency instead of the full one.

Kap
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