Odd Divisor Correct

Common Options : Enabled, Disabled

Quick Review

The memory clock speed of AMD Athlon 64 / Opteron processors is determined using this formula :

Memory Clock Speed = Processor Clock Speed / Memory Divisor

But instead of giving you the option of selecting any memory divisor you want, each Athlon 64 / Opteron processor has a fixed number of divisors designed to meet compatible memory standards. You can, of course, select any memory divisor you like even if you are using slower memory modules. However, it is still quite frustrating as each processor only comes with three memory divisors.

Perhaps with that in mind, AMD implemented a new feature called Odd Divisor Correct in all Athlon 64 / Opteron processors from Revision E onwards. It automatically rounds up any odd memory divisor to the next number, which is always an even number. It has no effect if the memory divisor is already an even number.

The odd memory divisor is always rounded up, thereby resulting in a lower memory clock speed. This rounding-up is done quietly in the background. So, you will not realize that your processor is using a higher memory divisor, unless you actually benchmark and compare your memory system's performance.

While it may sound like a useless feature, it can be used to gives you additional memory divisors that would not have existed otherwise. In the example of the Athlon 64 X2 6000+, enabling this feature would give you an extra memory divisor of 10 (when you select a divisor of 9).

As such, this is mainly a feature for overclockers. Judiciously enabling and disabling this feature will give you one or more additional memory divisors to play with. The number of extra memory divisors you can obtain using this feature depends entirely on the number of odd memory divisors in your processor.

However, if you do not overclock, you should disable this BIOS feature. Enabling it certainly will not improve performance. In fact, it will do quite the opposite.

Support Tech ARP!

If you like our work, you can help support out work by visiting our sponsors, participate in the Tech ARP Forums, or even donate to our fund. Any help you can render is greatly appreciated!