Geekbench is a completely awesome cross-platform benchmark that you can use for measuring the performance of your PC's processor and RAM.

Geekbench also offers the sexy Geekbench Result Browser which lets you compare your Geekbench scores with other Geekbench users.

Features:

Multi-threaded benchmarks:

Geekbench's processor benchmarks (every one!) run in both single-threaded and multi-threaded modes letting you see the performance increase multiple cores (or multiple processors) bring to your system.

64-bit benchmarks:

Geekbench is available in both 32-bit and 64-bit versions. Run both versions on a 64-bit operating system to see the increase (or decrease) 64-bit applications bring to your system.

Result Browser:

Submit your results to the Geekbench Result Browser and share your results with your friends and other Geekbench users. Create an account and keep track of your Geekbench results online.

SIMD benchmarks:

Geekbench features a number of benchmarks that use SIMD instructions (both Altivec and SSE) letting you see the performance increase SIMD-aware applications bring to your system.

Rosetta benchmarks:

Geekbench is available in both Universal and Rosetta versions for Mac OS X. Run the Rosetta version on your Intel-based Mac to find out how quickly it runs PowerPC applications, or to find out how much of a performance advantage Universal applications bring.