$ave Buck$

Let's admit it.

You want to build a Green Beast, but it's not always easy to figure out what the best component choices are.  And then there are those sandbaggers whining that it's too expensive to save any energy.  Don't give up!  First off, there are probably tweaks you can make to your existing rig without opening your wallet.

Even when spec'ing new gear, you don't always have to pay more to save energy.  It is not hard to find a graphics card, for example with higher performance and lower energy use than a more expensive competitor!  That said, sure, sometimes a more efficient equivalent part will cost more. We haven't done an exhaustive assessment--and the market is ever-changing--but our study and the detailed tables behind it will you a sense of the WIDE range of efficiencies as of mid-2015 that you'll find among commercially available components.  Choosing wisely among all the options can green your beast without costing more up front or compromising performance ... and your operating costs will be way lower.  Otherwise, run the numbers and decide if your money comes back fast enough.  Don't forget that for every dollar worth of  electricity you save in your rig, you'll be saving maybe 1/3rd more in air-conditioning costs in hot climates.

  • The U.S. EPA offers a set of no-cost power management recommendations for console users.  Check those out here.
Tuning your existing PC rig (thanks Larmion for a few of these):
  • In the course of our testing, we looked at changes in energy use as a function of thirteen different in-game settings (anti-aliasing, tesselation, shadow matching, color saturation, depth of field, etc.) during active gameplay, using the Fire Strike benchmark on our mid-range "M2" and high-end "H2" systems.  Many settings 5%-10% reduction in energy use, but some a good deal more.  Vertical synch was the stand-out exception, saving 18% on the M2 system and a whopping 46% on the H2 system.
  • Hunt down those powered slots on your motherboard with nothing plugged into them.  Some motherboards allow the user to disable components not in use (e.g., HDMI, PCI-E slots, RAM Slots, or SATA ports).
  • Current AMD GPUs (when in crossfire) offer "Zero-core" technology which means they can be powered down when the display is off.
  • Some GPU settings (e.g., AMD Catalyst or NVIDIA Control Panel) allow you to set a "performance" or "adaptive" power setting. Most games can have FPS set to a level of your choosing (say 60 FPS max). This allows your GPU to work less hard, especially in older games - without the difference being visible! For example: Civ 5 can make your GPU render the menu screen at several thousand FPS if you let it.
  • Choose the most efficient anti-aliasing algorithm available (MFAA or similar). 
  • Offerings like Microsoft's Direct-X 12 (within Windows 10) are boasting significant performance increases by utilizing more resources from the CPU, allowing the GPU to focus on other tasks.
  • Hardware acceleration in browsers could generate savings.
  • Keep your drivers up to date. Running many newer games can use less power after a few driver optimizations.
  • If time is too precious to shut your system down when you're not using it, or even put it to sleep, at least put your display to sleep when you're away.
  • Explore the power-management features in your OS.
When buying gear
  • Across the 26 systems we've tested we found a large variation in the ratio of power use while in active mode to that while on but idle mode. High ratios indicate that power management is effective; less power should be needed when the system isn't working. A couple of the consoles show virtually no difference in power use between the two modes, while others use nearly 2-times as much power while in active mode. The ratio for desktops ranges from about 1.3 to 4x, while that for laptops ranges from 2.4 to 6. The problem for buyers is that this information isn't readily available at the point of sale, but do ask for it or seek out measurements by third parties.
  • Survey the market with energy in mind.  Here is a snapshot as of mid-2015 to provide a sense of the wide variation in energy use for a given performance level.
  • Rightsize your PSU.  Efficiencies for most products max out at about 50% load.  Remember that nameplate power is often overstated by a factor of two, which could lead to a more expensive and less efficient PSU than necessary.
  • Avoid bottlenecks: DIY machines often end up with over-spec'd GPUs that their CPU or display can't even take full advantage of. Right-size components to work together.
  • Get into G-Sync or Free-sync - a new generation of display-side hardware/software that reduces tearing and other distortion normally encountered with less powerful (and less power hungry) GPUs.
  • Specify high-efficiency GPU architecture with staged control where unit has multiple processors (e.g., the NVIDIA GTX 900 series); fan-off at idle (e.g., EVGA's ACX 2.0 or ASUS's STRIX cooler).

  • Specify high-efficiency CPU architecture with low-power modes and what your processor will be doing.

  • Specify motherboards with switch-level controls (for empty slots), low power-delivery losses, power-connector quality.
  • Specify high-efficiency displays.
  • Look for variable speed control as function of multiple internal temperature sensor signals (M-Cubed T-Balancer Big NG). With the use of programs like Afterburner GPU users can specify desired fan speeds as a function of temperature. 
  • Go for fan-less PSUs or PSUs with a controlled fan curve (e.g., ones that have a "0db" fan mode). Enjoyer quieter operation as well.
  • Some case fans can be powered down when not needed if you adjust the fan curves in the BIOS (only Z97 and Z170 mobos apply).
Meanwhile, here are some broader strategies for the gaming industry and policymakers to chew on:
  1. Promote game designs to be more power-wise. There are no doubt software-side ways to write more elegant code that requires less power to achieve the desired gaming experience. Among the issues that require exploration are differences in energy use for titles distributed digitally versus on-disk.  Also of interest are energy-use changes due to mods, and on-line versus local play.  ENERGY STAR games, anyone?
  2. Standardized energy test procedures. Today pundits publish all sorts of inconsistent reports using home-grown test methods. For GPUs, one credible methodology are Linus Tech Tips' "GPU Showdowns" of AAA game titles.  Layering on energy use data would help gamers evaluate energy use and efficiency in the context of popular games.
  3. More product labeling. Currently only displays (EnergyStar) and PSUs (80 Plus) are labeled for energy efficiency.  Short of efficiency ratings, at least the nameplate power should be listed on the packaging of every product sold.
  4. Equipment energy performance standards.  There are a host of mandatory standards on the books for most imaginable equipment, from pool pumps to refrigerators to air-conditioning systems to lighting ballasts. As yet, there have been no standards for gaming PC components.  This is arguably more challenging than for most devices, given complex performance considerations and how rapidly the technology is evolving, but no doubt something is possible.
  5. Utility programs. Electric utilities spend billions of dollars a year on rebates and other sorts of voluntary programs and decision-support information to promote customer-side energy efficiency. We are not aware of any utility that has done so in the gaming space.
  6. Improved consumer decision tools.  At present, only the most dedicated consumer can sift through the scant information in the market about energy efficiency, and even then, we have found that labeled (nameplate) power requirements are often way off -- by a factor of two or more.  Third parties from within the industry or outside it could assemble better tools for helping consumers make better energy choices.  Imagine PC PartPicker with a built-in energy calculator and bottleneck-detection alerts.  The role that behavior (hours of play, overclocking, etc.) plays on energy use is another factor that can be quantified and telegraphed to users.
  7. Finer industry segmentation data. Better data can help refine estimates of current and projected energy use, and to target efforts.  This includes sales and installed base by geography, use in workplace contexts, user preferences (e.g., numbers of graphics cards), etc.
Subpages (1): Market Survey