Check Windows 7 power saving mode, try putting it in high performance. Also open the task manager and make sure your CPU usage is > 5% before you start the Winrar benchmark, if other processes are using the CPU it will lower the benchmark results.
My E6750 (dual core) @ 3.52 get about 1,500. An E7400 @ 4.07 scores about 1,300.
The 6750 has more cache and a higher FSB and RAM to help it.
I have never seen people compare Windows 7 Benchmarks of Winrar.