Replies to post #66899 on Advanced Micro Devices Inc (AMD)

[alan81]

I don't think this is what you think it is...
According to the document specified here:
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/30417.pdf

This is the key information that I have gleened from this document so far. We start with table 9 which is on page 10.
This table contains several columns. Each column is for a different heat sink with values ranging from .2C/W to .53C/w. Different opteron products will reference a different column, as such AMD seems to be specifying the theta CA (case to ambient) for a given OPN. Note that you can generate these tables on your own by calculating Power=(tcase-tambient)/thetaca AKA Thermal resistance. Note that this thermal resistance is the proportionality constant I was talking about in my earlier post.

Now we move down into a product specification... lets pick the first dual core opteron which is on page 35. The first part listed has an OPN of OSA865FAA6CC. We can decode this to mean OS=opteron server, A=standard power, 865=part number, F=940 pin package, A=variable voltage, A=variable tcase, 6=2MB cache, CC= rev. E (wheew!!) Note that this means I order a part with "variable Tcase".

The first specification is Tcase max, which is variable between 49C and 67C. If we look at table 9 we find the 49C part has a TDP max of 28W, while the 67C part has a TDP max of 95W.
The notes indicate that:
Tcase max is programmed during device manufacturing with part-specific values for Rev E and later processors
with 'Variable' indicated by the Case Temperature OPN character, and can be any valid Tcase max value in the
range specified for the corresponding OPN.
In other words, if you order part # OSA865FAA6CC you may get a part with TDP of 28W or you may get a part with TDP of 95W... you really don't know. What you do know is that if you put a heat sink and fan combo on it with a theta CA of .25C/W (or better) and operate with an ambient of 42C or lower, you are good to go.
Hope that makes sense.

To take this in a bit of a different direction based on your earlier comments. I believe you were indicating you expected AMD to introduce a dual core Turion with a Tcase of something like 65C and perhaps a TDP of 35W. I believe this would certainly be possible. The problem is that this part would require the same heat sink as a part that was specified for a Tcase of 100C with a TDP of around 70W.
Clarifications and questions welcome,
Alan