A computer’s power supply converts the AC power from your home or office into the Direct Current that your PC needs to operate, then distributes that power to each individual component. What does an individual Power Supply’s wattage or its efficiency rating mean? And how much wattage do you need in your new trading computer?
Wattage and Efficiency
To start, power supplies have two basic ratings to be concerned with – wattage and efficiency. The wattage is simple; it’s the maximum amount of power the supply can output when under a 100% load. So a 600W power supply can distribute UP TO 600 watts to the PC’s components. Take note – this does not mean that you’ll be pulling a constant 600W though.
The efficiency rating is how well (or how efficiently) it converts the AC power to DC, or to look at it the other way, how much power it wastes during that conversion. For example, a Bronze Rated power supply, which by definition must be at minimum 82% efficient at full load (with higher efficiency at lower loads), will output 82% of the inputted AC power to DC, losing 18% of the original wattage to heat. That means that a 600W Bronze Certified PSU with an 82% efficiency will draw about 730W in order to output the 600W.** Ratings go up from Bronze to Silver, Gold, and Platinum in that order of efficiency. Higher efficiency power supplies aren’t just great for energy savings, but also tend to last longer because a less severe heating/cooling cycle, so we do typically recommend the most efficient PSU your budget will allow, especially for trading computers.
**Remember, that’s only under full load – a PSU will only draw what it needs to.
Matching Wattage and Efficiency to Your Custom Components
A critical element to the configuration of your PC is ensuring the PSU you choose is robust enough to output the power needed to run the components that you’ve selected, with a bit of headroom to spare. Consistently maxing out your power supply is not the best recipe for system longevity. Here is a very rough list of the estimated power consumption of your vital PC components, though obviously these numbers vary for each specific component.
- Mid-range graphics ~165W
- High-end graphics ~350W
- Mechanical Hard drives ~9W each
- Solid State Hard Drives ~3W each
- Haswell CPU ~75-90W
- Haswell-E CPU ~140W
- Motherboard ~30-80W
- RAM ~3W per stick
- Optical Drives ~25W
As you can see, the graphics card (or cards) will be the biggest power draw in your PC with some top end graphics pulling 350W+ each while under load, although significantly less at idle. But even with several hard drives and a Haswell CPU, a 600W power supply is sufficient for most single GPU configurations. For multi-GPU systems, we typically recommend at least an 850W PSU, with 1000W (or more) needed for 3x GPU configurations.