Modern AMD and Intel processors are fantastic feats of engineering, packing billions of transistors inside a tiny package. Over the decades, we've seen improvements made to the number of physical cores available for processing instructions, increased clock speeds to allow the central processing unit (CPU) to handle more instructions per cycle, and more efficient architectures to get as much performance per watt as possible. Most recent CPUs from AMD and Intel will automatically and dynamically boost depending on power and thermal constraints.

For AMD, this is largely handled through its Precision Boost Overdrive (PBO) feature. By default, PBO is disabled on all motherboards, though you may see the setting "auto," which disables it from boot but allows AMD Ryzen Master to activate and configure PBO, much like you would through the motherboard firmware itself. After enabling and configuring PBO either through Ryzen Master or the UEFI firmware, the AMD CPU would boost to higher clock speeds, adjusting voltages and power limits on the fly.

This can increase CPU temperatures across the board, which is where Energy Conservation Mode (ECO) comes into play. Using a combination of PBO and ECO will allow you to get as much from your AMD processor without causing your cooling solution to ramp up into overdrive. The two technologies are impressive, and we're going to dive into how they work and why I always configure my AMD-powered builds with both enabled.

The marvel that is PBO

Automatic overclocking

Before this feature, overclocking your CPU was an art. You had to spend countless hours, if not longer, fine-tuning your CPU through a few variable changes. Boot the system, run some stress tests, return to the UEFI, and make adjustments. Rinse and repeat. It was amazing to see how far we could push processors, and many still choose to do so today without the help of automated features and algorithms. Still, PBO is essentially an easy way to automatically overclock your CPU, taking all the guesswork out of the process.

AMD CPUs have marketed boost clock speeds that the chip will attempt to maintain under load. To get more out of the CPU, PBO allows the CPU to go beyond its maximum configured voltage and power delivery limits set at the factory. So long as the required thermal headroom is available, usually in the form of all-in-one (AIO) liquid coolers, the CPU can dynamically tune itself whilst continuously monitoring temperatures, power consumption, and workload to adjust PBO configurations in real-time. Think of it as overclocking on the fly.

PBO works by using the CPU’s System Management Unit (SMU) firmware to adjust three power and thermal parameters. The first is package power tracking (PPT), dictating how much power is allowed into the CPU as a whole, followed by thermal design current (TDC) for the maximum allowed sustained current, and finally, electrical design current (EDC) for current through bursts and peak demand. And again, everything is adjusted on the fly as you use your PC. It's very much a set-and-forget type of affair.

Although PBO is fully automated, there are variables that can be set by the user. This is largely in the form of power limits, for instance, 150W. This allows one to configure PBO with cooling and power supply in mind. Using PBO allows for improved performance at the cost of thermals. The more power used by the CPU, the hotter the package gets and the more waste heat is produced. That said, improved in-game FPS, faster rendering times, and more capable multi-core computing usually more than make up for this drawback.

So long as you have adequate cooling attached to your Ryzen CPU, you shouldn't have any trouble activating and using PBO. How far you can push the CPU through PBO depends on various factors, namely, power and temperatures. The best part about PBO, however, is the ability for this overclock to be completely disabled with a click of the button.

Saving energy with ECO

Reducing power across the board

If PBO is all about setting your CPU values to 11 to get as much out of it, ECO helps to reduce power through lowered power limits and thermal management during idle or lighter workloads. It's primarily used for compact devices where heat and power limitations are more strict, but it can be useful for full-size desktop PCs, too. An AMD Ryzen 9 CPU in 105W ECO mode might behave more like a 65W Ryzen 5 or Ryzen 7 chip. The performance drop is usually modest at around 5–10% in most workloads from our testing, but the reduction in heat output and cooling noise can be significant.

Instead of setting hard power limits, ECO can be configured to work alongside PBO to balance power and efficiency. If you'd like to increase power slightly or enjoy a stock experience with lower draw, PBO and ECO can be an ideal solution. Like PBO, ECO is exposed within Ryzen Master and can be found in similar places within UEFI firmware, making it easy to toggle between maximum performance and efficiency, or combine both and enjoy a more versatile computing experience. While you would assume these features are mutually exclusive, they're not, and that's what makes it amazing to use.

Using PBO and ECO together

The best of both worlds

As aforementioned, we can use PBO and ECO to work together and produce a more potent CPU for gaming and other intensive workloads. By default, the CPU will boost accordingly, but activating PBO would increase this to custom set limits through Pbo itself. ECO would then run in the background to optimize efficiency when needed, ensuring the CPU doesn't waste power at lower loads or when idle as well as keeping power draw as low as possible. Configuring lower power limits, returning to that earlier 105W example, enables us to keep the CPU from running wild.

It's the best of both worlds, allowing PBO to stretch the CPU's legs during intensive workloads and conserve energy when only partial performance is required. Let's use the AMD Ryzen 9 9950X3D as an example here. Unrestricted, this CPU can run at 200W or so. We can enable a 105W ECO mode as well as PBO. Under gaming or bursty workloads such as image processing, the CPU can fully boost within its PBO constraints, far beyond stock limits, but under sustained multicore loads, the reduced PPT cap prevents runaway heat and power draw.

The aim is to provide PBO with as much room to boost without going above the ECO power budget. With just PBO enabled, you're unleashing the full potential of the processor. ECO without PBO would see an efficient AMD system without all the extreme boosting. But running ECO and PBO together allows for a more efficient system without hampering performance too heavily. The tradeoff between losing a few percent of performance (a few FPS within the CPU-intensive X4: Foundations), but lowering heat and power draw considerably, is worth it for my system.

Give it a try on your system to see how you go. Depending on the rest of your PC hardware and how PBO and ECO are configured, you could see a sizable improvement to power draw and thermals while barely touching performance.