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-   -   N900 Hardware (https://talk.maemo.org/showthread.php?t=33526)

TA-t3 2009-10-30 10:12

Re: N900 Hardware
 
As for overclocking, the Pandora overclocking numbers are (obviously) from chips produced earlier. Since then TI has apparently started speed-sorting their chips, and those that can handle a higher frequency go into a bin with a different ID and, presumably, different price (this is fairly normal practice btw). So it may be that on production model Pandoras and N900s there will be fewer of them that will actually overclock well.

Rushmore 2009-10-30 13:53

Re: N900 Hardware
 
Quote:

Originally Posted by texaslabrat (Post 361248)
Speaking in very rough numbers, the cortex A8 has about 4 times the number of transistors as ARM11. However, when cortex A8 is manufactured on a 65nm process, the actual size of the chip is roughly twice the size of the ARM11 core when the ARM11 is manufactured on a 90nm process and thus twice as expensive as that ARM11. If they were both manufactured on a 65nm process to maintain an apples-to-apples comparison...the Cortex A8 would be about 4 times as large, and thus about 4 times as expensive to make as that hypothetical 65nm ARM11.

Without going into *too* much detail... large volume IC manufacturing costs are very strongly linearly related to the size of the chips (within the same technology "generation/family" eg SOI, strained silicon, copper interconnects, etc) due to the built-in costs of the wafers they are made from as well as the staggering up-front capital costs for the equipment.

Hope that clears it up a bit.

Wafer yield is the other issue. Run into diminished returns at some point. Scrap is a the big nasty here as far as total cost of process. SPC in these processes are always looking at the yield curve of good chips.


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