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Old 2007-06-07, 22:23   #62
geoff
 
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Mar 2003
New Zealand

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Here are the approximate break points between FFT sizes for SSE2 machines:
Code:
FFT size   Break point
--------   ------------------
448/512    4522000 / 4523000
512/640    5126000 / 5127000
640/768    6423000 / 6424000
768/896    7652000 / 7653000
896/1024   8912000 / 8913000
If sieving for the 5-10 million range reaches the high point for the 1.5-5 million range (4200G) well before LLR reaches the 448/512 breakpoint, then maybe it would be worthwhile including the full 512k FFT range, i.e. sieve 4.5-10 million.
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