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Old 2009-12-09, 01:37   #54
geoff's Avatar
Mar 2003
New Zealand

13×89 Posts

These are the current per core sieving rates I am getting on my 2.66GHz Core 2 Duo:

32-bit: 7.6M p/s (1T in 36.5 hr)
64-bit: 13.3M p/s (1T in 20.9 hr)

The 64-bit executable will start to slow down as the sieving depth approaches 2^51 (about 2252T) due to the need to correct SSE2 rounding errors. Once depth reaches 2^51 the code will switch over to using the x87 FPU. When this happens the rates will be:

32-bit: 7.7M p/s (1T in 36.1 hr)
64-bit: 12.2M p/s (1T in 22.8 hr)

The speed should then only increase very slowly (if at all) as the sieve depth increases.
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