I've been trying to figure out why one of the Dell E6410s that I provided to Arisia was much slower than the others. The two in question are both being reported by the Dell BIOS and Win7 and i5-M520s running at 2.40GHz. One is coming up with Novabench numbers of in the mid 400s and one is coming up with Novabench numbers in the mid 500s. The second is what I would expect given two other Dell E6410s (an i7-M620 running at 2.67GHz and an i5-M560 running at 2.67GHz) are coming up with Novabench numbers in the mid 500s. The two in question are both running with the same amount of DDR3-1067 memory (2 2GB DIMMs) and the similar 500 GB 7200 RPM hard drives and using the default Intel GMA HD graphics and the latest E6410 A16 BIOS and the same version of Win7 Ultimate 64bit with the exact same software installed. The hard drive cache size etc. really shouldn't matter since the difference is in the Novabench CPU sub score.
Careful inspection of what the BIOS is reporting shows that one has a CPU Processor ID of 20652 and one has a CPU Processor ID of 20655. Googling that shows that while they are both Arrandale / Capella / Westmere chips, but the "faster" CPU Processor ID of 20655 is actually an i5-460m which other benchmarks show as performing better than the i5-520m!
Now, the bottom line question is why are both the Dell BIOS and Win7 reporting both incorrectly as i5-520m rather than one as an i5-460m? I wonder if this is really just a BIOS bug that then gets passed up to Windows.