BEN HARDWIDGE HOW IMPORTANT IS EFFICIENCY?
Power efficiency might not have the instant appeal of superior graphics and performance, but we should take it seriously, argues Ben Hardwidge
fficiency just isn’t sexy. I’ve watched marketing managers try to talk enthusiastically about performance per watt, and it must be like trying to get excited about loft insulation. Better graphics are cool. Faster computers are cool. Even bragging rights are cool. But lower power consumption? It’s tough, because there’s no immediately visible benefit.
But while efficiency might not be the stuff of hardware geek fantasies, it’s a major factor when it comes to my buying decisions. While we were sorting out the scoring system for last month’s GPU Labs test, we settled on a 10 per cent score for efficiency again, but I wonder if that’s enough now. There’s a gulf between Nvidia and AMD’s GPUs when it comes to power efficiency, where our test system drew 266W from the mains with a GeForce GTX 970 installed at load, but that figure rocketed up to 437W with a Radeon R9 390 in place. That’s a difference of 171W, and it will increase further as you add more cards.
Efficiency now concerns differences of hundreds of watts, and for very similar performance. Aside from any concerns about your carbon footprint, that’s bad news if you’re a PC gamer. With the higher heat output of non-efficient hardware, you’ll need more powerful and often noisier coolers, as well as more airflow in your case to help expel the hot air. It also limits how much hardware you can install in your case. I wouldn’t want three Radeon R9 390X cards in my system without some decent space between them for airflow.
Poor efficiency also limits what board partners can do with hardware, such as making small cards with small coolers. What’s
Emore, it limits your choice of system. You could comfortably build a tiny GTX 970 rig with an SFX PSU, but not with an R9 390. Then there’s the cost of electricity, and once you get into this territory it stops being negligible, particularly if you use your PC for gaming a lot. Choosing an R9 380 over a GTX 970 is almost like leaving an extra three 60W lights on in the house while you’re gaming.
GPUs aren’t the only issue. CPUs can also eat a lot of electricity at full whack. Intel has nailed efficiency with its latest Skylake kit, with CPUs such as the Core i3-6100T having a TDP of just 35W, making it ideal for our HTPC build (see p88). Likewise, the Core i7-6700K’s TDP is only 91W, which is an amazing achievement compared with the 220W TDPs of AMD’s topend FX CPUs.
Efficiency is AMD’s big problem at the moment, partly because it’s still depending on a GPU architecture that’s nearly four years old, but AMD also seems to be dismissing efficiency as unimportant. In terms of performance and features, AMD’s kit is still competitive, but that isn’t enough now. When I look at what hardware to buy, I’m also thinking about the heat output and power consumption, particularly when the differences involve hundreds of watts.
For me, efficiency is now a major factor when it comes to buying decisions, even if it isn’t particularly exciting, but I’m often told that enthusiasts don’t care, and that performance and frame rates are the priorities. Is this true? Do PC enthusiasts really not care about heat output and power consumption? I find it very hard to believe, and I’d be interested in your thoughts. Drop me a line at email@example.com