Overclocking, Smart Profiles, and ceramic impellers
As I mentioned earlier, AMD's OverDrive utility has a new Smart Profiles feature that, to some extent, mirrors the functionality of the Turbo Boost capability built into the Core i7. Smart Profiles are, in some ways, more like the game profiles built graphics drivers for multi-GPU schemes such as SLI and CrossFireX, because they're based in software.
Here's how it works: the OverDrive utility has a set of profiles for many of the most popular current games. Updates to the list are downloaded automatically once a week by the OverDrive utility when it's first run. The profiles contain information about how many threads a game is likely to use and how the CPU should behave in it. Here's an example, a profile for 3DMark05 taken from AMD's website:
If Smart Profiles are enabled, several things happen automatically when the profiled application is launched. The OverDrive helper service sets the thread affinity for the application to cores 0 and 1. Those two cores are overclocked slightly, in this case by one full multiplier tick beyond the stock speed. Cool'n'Quiet dynamic clock speed scaling is disabled, as well, and the cores not used by the application are clocked down, core 2 by one tick and core 3 by two ticks. The profile also has settings for custom CPU voltage, process affinity, and whatever "Boost State" happens to besorry, not sure on that one.
As you might imagine, invoking a profile can provide a performance boost. AMD estimates those gains rather conservatively at 2-4%, depending on the application. Given the way it works, though, the Smart Profiles feature has some big limitations. For one thing, you'll need a Black Edition processor in order to take advantage of the multiplier-based clock speed increases. Also, since this is technically overclocking, stability isn't guaranteed. And this function won't even work without a profile for the game or application you're using. AMD maintains those profiles, determining what's best on a per-application basis by while attempting to honor its CPU TDP targets and avoid instability.
Right now, profiles are very conservative; they don't go beyond one tick up from the default multiplier, in part because profiles don't include any processor-specific instructions and so have to be very generally applicable. AMD's Sami Makinen told us the company is considering expanding the information included in profiles to provide CPU model-specific instructions that might grant it more leeway in cranking up the clocks. He also said the firm is considering including an option to enable Smart Profiles by default when the OverDrive application is installed. That could prove helpful because, right now, one must switch the utility into Advanced mode and then click a cryptic checkbox labeled "Application list" under the Smart Profiles tab in order to enable it.
Given all of their limitations, Smart Profiles in their present form aren't likely to be much of a help for the Phenom II against what we expect to be a very aggressive Turbo Boost implementation in Intel's Lynnfield processors. Still, this is an interesting feature that holds some potential as a tide-me-over until AMD can implement a Turbo Boost-like capability in future silicon. The fact that users can create their own profiles opens up some intriguing possibilities, as well.
Curious to see what sort of gains Smart Profiles could achieve, I enabled them and tested Far Cry 2. Check it out:
Yeah, so two frames per second won't set the world on fire. I'm still curious to see how far AMD takes this capability in software.
Using more traditional methods, I was able to get our Phenom II X4 965 chip running stable at 3.9GHz, courtesy of beaucoup cooling and 1.5V of juice. That produced more dramatic performance results.
Not bad, eh? I don't think the CPU temps went beyond 60°C with our Cooler Master Hyper tower air cooler.
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