Amd Phenom x3 vs Amd Athlon x2, 3 core slower than 2 core

Performance: Phenom X3 8450 15% Slower

The small Phenom X3 model, the 8750, clocks at a rate of 2.10 GHz. When compared to the Athlon 64 6400+ with 3.20 GHz and 6000+ with 3.00 GHz, it simply can’t keep up for many applications.

The 6400+ is approximately 15% faster than the Phenom X3 8450 in the benchmark course. Compared to the 6000+ it is almost 9% slower. The difference in price between the small Phenom X3 and the Athlon 64 X2 6400+ is 26 euros and it costs approximately the same as the Athlon 64 X2 6000+.

source:http://www.tomshardware.com/