New AMD Chipset Drivers Tested on Ryzen 9 3900X 74

New AMD Chipset Drivers Tested on Ryzen 9 3900X



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AMD took the desktop processor performance crown this month with its 3rd generation Ryzen processors, which introduce several architectural changes while retaining backwards compatibility with socket of older AM4 platforms. Like most new technology, 3rd generation Ryzen isn't without some initial issues to iron out, and AMD is bug-swatting on two fronts: its 3rd generation Ryzen processors and its Radeon RX 5700 "Navi" graphics cards, both debuting new architectures. 3rd generation Ryzen processors do indeed live up to the promise of backwards compatibility and offer significantly higher performance than the 2nd generation Ryzen, but users reported certain problems to AMD.

The first and major problem were idle clock speeds, voltages, and power draw. Apparently, these processors are restive and don't idle at low clock speeds the way people expected. AMD was quick to point out that this is a case of the "observer effect", where monitoring software and other low-priority apps are causing the processor to think there is need to wake up more cores and raise clock speeds and voltages.

The underlying issue is the rate at which "Zen 2" processors and the operating system talk to each other about required processor power. This is a staggering 1 ms compared to 15 ms on most processors. When you have a large number of low-priority applications requesting CPU time, or certain kinds of monitoring utilities trying to measure processor stats, a "Zen 2" processor is under the false impression about the performance demand and perceives these utilities and software as load that warrants waking up the cores, and raising the frequencies.

With "Zen 2", AMD introduced a platform feature called UEFI CPPC2 (UEFI collaborative power and performance control). This capability puts the processor's on-die firmware in complete control of clock-speed/voltage selection at all times. The processor can make these changes at breakneck speed, once every 1 ms. Out of the box, Windows 10 cannot keep up with this speed as its stock "Balanced" power scheme messages the processor with performance-requirement requests only once every 15 ms. AMD hence installs a custom power scheme via the Chipset Driver called "Ryzen Balanced Power Plan". This makes the OS and processor talk to each other every 1 ms.

When not gaming or working, the average PC enthusiast's machine is running a web browser, chat application, peripherals application, and a monitoring app which polls hardware. The processor could interpret their load as a need for boost if the processor and OS are talking to each other at 1 ms. This gives users the appearance of a processor that's stuck at a higher state than idle.

AMD's solution to the problem is an updated Chipset Driver with an updated "Ryzen Balanced" profile that drops the rate at which the processor is receiving performance requests from the OS to 15 ms when the processor is idling, and to speed up that rate to 1 ms when faced with a "real" workload. The drivers also change the way the processor behaves at low workloads. Any core that isn't power-gated will sit at 99% of the processor's nominal clock speed. This 99% value keeps the active core on the verge of boosting, so that any "serious" workload can easily trigger CPU boost and send the processor back to the 1 ms polling rate.

AMD implemented this change, and more, using the new Chipset Driver version 1.07.29 available for download on the AMD website. The update is only recommended for 3rd generation Ryzen users as older generations of Ryzen don't feature CPPC2. In this review, we pair the Ryzen 9 3900X through our whole CPU testing suite, including both applications and games, to determine the performance implications this new chipset driver brings with it. We only uninstalled the old chipset driver and installed the new software, everything else remains untouched.

Performance Results

When looking at application performance we can quickly identify two distinct groups—single- and low-threaded applications and fully multi-threaded apps. While the former all gain quite significant performance, the multi-threaded tests do see a small performance loss.

For games, the new chipset driver is a clear improvement with nearly all titles posting performance improvements, especially at the higher resolutions, which are relevant for gamers.

Power Consumption

We also tested power consumption, which shows negligible differences—not unexpected given the small performance changes.

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