Dynamic Overclocking / Smart Profiles

One major source of grief over the past few months has been Intels Turbo Boost technology - at least for some people who thought it a devious, deceitful spin to fake performance that only existed under extremely tight controlled lab conditions. Even if we were to subscribe to this point of view, Turbo Boost is an elegant way of bridging the transition between software poorly optimized for symmetric multiprocessing (including Microsoft Operating Systems) and truly multithreaded software or even virtual machines. In the first scenario raw clock frequency rules, in the second situation thermal and power situations are setting the limitations for the operating envelope.

Consequently, having a flexible solution that scales with the number of busy cores - or rather inversely with the number of threads - is the best of two worlds. Intel implements this solution on the BIOS level - after all, each core domain has its own clock anyway. AMD processors had their individual clock domains quite a bit longer than Intel but for whatever reasons, AMD never implemented this kind of solution - until now that is. In contrast to Intel, however, AMD is going a different route, and uses the AMD Overdrive Utility to selectively bind certain profiles to certain applications, in which the "loaded" cores are cranked up 2 multiplier stops or 400 MHz beyond the nominal top frequency and the "idle" cores are clocked down by 400 MHz. Bear in mind that the Smart Profiles only apply to Black Edition CPUs, if the muliplier is locked internally, then AOD will not be able to raise it in software either. Profiles can be downloaded from a dedicated AMD server by simply clicking an "update" button in the AOD GUI. These profiles will become public domain sometime in the next week or whenever AMD's legal department signs off on the nitty gritty.

Smart Profiles will be available in the next few days

Up-close and personal

Some of the "Smart Profiles" details are still a bit sketchy, particularly with respect to the necessity of down-clocking the idle cores which could be done in a similarly efficient manner by simply using P-states or C'nQ. However, as we and others found in the past, the wake-up and ramping delays in the case of C'nQ, to bring an idle core up to speed can have some rather harsh effects on the outcome of benchmarks, which can be avoided by using the Smart Profiles-based clocking scheme.

Black Edition Memory Profiles

An additional novelty is introduced under the acronym BEMP, short for Black Edition Memory Profile. The way BEMP works is that AOD will read the hex string of the memory part number from the SPD and cross-check with a dedicated server hosted by AMD for any profiles corresponding to the particular part number. If there is a match, the system will download the profile in XML format which is then read by AOD and allows updating of the memory settings "in software" which, in most cases, will require a reboot upon which the new frequency and timing parameters are loaded.

Sounds familiar? In essence, it is the same thing as what nVidia has been pushing with their EPP and Intel with their XMP profiles. Personally, I actually prefer AMD's solution, if for nothing else but the simplicity of the approach and the fact that no special programming of the memory modules is required. In fact with a little bit of hacking, BEMP is appliccable to any memory module, since AOD also allows simple "importing" of profiles that can be edited in notepad according to any user's wishes.

Black Edition Memory Profiles

Profiles can be loaded through a cross comparison of the module part number with the AMD-hosted data base...

... or else imported from the system drive.

The profiles corresponding to any specific part numbers can be downloaded as XML feed from AMD's server. AOD also allows to import profiles in XML format from the hard disk. We will show a bit later that DDR3 memory bandwidth is effectively limited by the NB/DC frequency, that is, there is hardly any improvement from going from DDR3 1333 to DDR3 1600, unless the NB frequency is increased as well. To address this issue, AMD allows AOD to ramp up the NB frequency to 2.4 GHz if a BEMP with 1600 MHz data rate is selected. 2.4 GHz is safe for all Black Edition processors whereas higher frequencies may either be a matter of luck or else require increasing the supply voltage.