It says it right there in the article on what you can do:
"The default processor clock frequency multiplier of our Athlon 64 X2 3800+ equals 10x, so the only thing you can do with it is to make it lower (due to Cool'n'Quiet support).
As a result the CPU can only be overclocked by increasing the clock generator frequency. In order to avoid being limited by the potential of the other system components, we locked the PCI and PCI Express bus frequencies at their nominal values for the entire test session, and the multiplier for Hyper-Transport bus was reduced to 4x.
The memory frequency was also set with a reduced divider value, which would guarantee that the DIMM modules would work for sure even when the clock generator frequency grows up.
During our tests we found the maximum clock generator frequency when the processor remained stable. It was 240MHz. To go beyond this limit we had to slightly increase the processor Vcore: we raised it to 1.45V. The resulting CPU frequency in this case made 2.4GHz."
