Proto že jsou různé revize a ten s ktým to porovnáváš se už nedělá.
Jinak -
AMD Athlon II X4 640 Average CPU Mark Description:
CPU First Benchmarked: 2010-07-01
CPUmark/$Price: 34.71 Overall Rank: 139
Last Price Change: $99.99 USD (2010-12-31)
3471

AMD Phenom II X4 945 Average CPU Mark Description:
CPU First Benchmarked: 2009-04-21
CPUmark/$Price: 26.68 Overall Rank: 125
Last Price Change: $134.99 USD (2011-01-19)
3601