Tom's Hardware investigates how well the new AMD Phenom architecture scales and compares it against the old Athlon architecture:
While the core to core analysis provides interesting results about architecture performance across typical benchmarks, it does not answer the question that will eventually be crucial, once Phenom's TLB issues are fixed (B3 stepping) and the chip is available at higher clock speeds in quantities. The question is simply whether the quad core will scale well enough to attack Intel at the high end. In other words: Will clock speed increases translate into higher performance gains than just similar clock speed increases with an Athlon 64 X2? And at which clock speed will power consumption become an issue?
Of course we wanted to get some answers, so we grabbed our test system again: the Asus M3A32 MVP using AMD's 790FX chipset, an Athlon 64 X2 6000+ processor, a Phenom 9000 engineering sample (unlocked), two 1 GB DDR2-800 DIMMs by Corsair, our Western Digital reference hard drive, and Gigabyte Radeon HD3850 reference graphics card. We ran both processors at 2.2, 2.4, 2.6 and 2.8 GHz clock speeds, to see how well the clock speed increase translates into additional performance.
Check it out over here. In their tests THG noticed the Phenom is faster than the Athlon 64 in all tests but unfortunately they also saw that the new architecture doesn't scale as well. This means performance gains of Phenom chips with higher clockspeeds will not be as significant as they have been with the Athlon 64 X2 cores