Besides the odd PC or networked media player, there’s usually more equipment silently running in the background. All these independent devices combined use up more energy then you might think. And to my surprise, one device, supposed to reduce power consumption, was actually doing the exact opposite.
USB connected NAS
My main router is a Linksys E4200 V2. Great signal range, very stable, adequate tool set and it provides a USB input to turn a USB hard drive into Network Attached Storage. One major advantage the V2 has over the V1 is it’s improved read/write speed for the USB connected storage. The NAS’ intended use was for backups, but the increased networking speed meant it was way faster compared to my PopcornHour C200 (22 MB/s vs 13 MB/s). It quickly became the repository for files I needed fast access to. Tasks like browsing through photos over the network can be painstakingly slow with the C200 but doable from the E4200’s NAS. For streaming purposes the PopcornHour was still fine though.
The E4200 has one disadvantage; it doesn’t allow the USB drive to power down. No power management whatsoever. We’ve seen in part 2 a spinning vs. an inactive hard drive doesn’t necessarally mean a large drop in power consumption, but it always helps. More important, an extra USB drive means the use yet another separate power supply.
A power supply will never be 100% efficient. This inefficiency means heat production and current leakage. So part of the overall energy is lost. Because of this, it’s better to connect multiple devices to a single larger power supply instead of using a separate one for every single device. Unfortunately, that’s not always an option. For example, the maximum current a USB 2.0 port can provide is limited to usually 500 mA (at 5 volts, so just 2,5 W). That’s nowhere near enough for most USB hard drives. Enough talk. Out comes my Fluke 87 multimeter. The power used by this secondary NAS? 74 milli amps (= 17 watts or 149 kWh a year). Not that much on it’s own, but it adds to the bigger picture.
Master-slave power socket
In an earlier attempt to save some energy, I purchased a master-slave power socket. For you who don’t know what that is; it’s an extension socket with one master and several slave outlets. Plug your main device, e.g. a PC, into the master and peripherals you tend to use together with the PC into the ‘slaves’. Once turned on, the power used by the PC passes a certain threshold pre set in the socket which in turn switches on the slave outlets, powering all ‘slave devices’. If the PC turns off, the power falls below the threshold and all peripherals plugged into the slave outlets are completely shut off, effectively eliminating standby currents from adapters and other inefficient power supplies, saving you a few watts.
But here’s the thing. The socket itself uses energy for it’s internal circuitry too. A whopping 16 watts of power! In my case 12 watts more then the standby power leakage of all slave devices combined! It seemed a perfect solution, but ended up doing the exact opposite of it’s intended purpose. I immediately replaced it for a normal switched extension socket. Another annual saving of 105 kWh.
Let’s add it all up
I tried to give a picture of the devices, their role and their power consumption, I use on a daily basis for all my multi media needs. At home, at work or on the road. On my main TV set and streaming to multiple iOS devices over my LAN of WAN. Here they are again with their idle power usage:
- PLEX server PC: 51 W
- PopcornHout C200: 42 W
- Secondary NAS: 17 W
- Backwards Master-Slave socket: 12 W (usage minus savings)
Added up, that’s 122 watts of continues use which means 1068 kWh annually or, at 22 cents per kWh, the total sum of 235 euros.
So… what to do about it
Those of you who’ve read part 1 and part 2 might have guessed; I ordered a Mac Mini. Currently on sale for 499,- euros. The specs state it will only use 11 watts when idle (with Finder open as Apple likes to put it). I will need to connect an additional hard drive to it to house all of my files. But because of the Mac’s power management features, it will use less power then it does connected to my E4200. I estimate the setup will use an average of 20 watts. That’s 175 kWh (38,55 euros) a year. A difference of 893 kWh or better yet, 196,45 euros! The Mac Mini will earn itself back in a little over 2,5 years, not to mention the extra functionality compared to the PopcornHour C200 and it’s resale value once I inevitably switch over to another toy.
Stay tuned for my articles on how I turn a Mac Mini into a proper media center.
This is the second out of three blog entries about my quest to reduce te energy conscumption by the 24/7 media equipment I use at home. The first device was my PC. You can read up here.
Next up is the PopcornHour C200. Within the chain of devices, this one is probably used the most. It’s my primary NAS, it contains all video- and audio content and is connected by HDMI to my Samsung 40D8000. Another great feature is it’s ability to take care of all NZB downloads. So it’s my workhorse, but how much do I actually feed it.
First a little background on the C200. It’s made by PopcornHour (Syabas), the leading brand in networked media tanks. Which basically means as much as a NAS with video output capabilities. It’s build around a Sigma SMP8643, 667MHz floating point processor/video decoder. The macrovision brother SMP8647 is found in many blu-ray players. Out of the box, there’s a load of supported file formats and containers. There’s a very active community with lots of great third party apps and modules, most of them free. So, it has a lot going for it, but despite it being a second generation device with a large costumer base, you get a lot of cons with it as well. Lets start with the good:
- Great picture quality
- Integrated NAS, download and media playback device
- variety of network protocols like NFS, SMB, FTP, etc.
- RF remote, so no line of sight necessary for control
Now for the bad:
- Lack of firmware updates while containing a lot of bugs , specially in the first year after release
- While advertised as 10/100/1000 network capable, the network speeds are nowhere near gigE
- Power supplies die like crazy! It’s all over the main support forum
All that aside, it is a great device that supports most of my media needs. But power consumption is the topic so here goes!
At popcornhour.com, it’s rated 13W when idle with no extra devices attached. This means no must-have-internal-hard-drive which instantly defeats the purpose of a ‘media tank’. So the specs are useless. And there’s another issue. Like many others, my power supply died after two years. Probably due to heat build up. It uses passive cooling for noise reasons. Knowing a bit of electronics I can say the power supply is of bad design and bound to fail under heavy and continues use. I replaced it with a standard ATX PSU taken from a HP thin client PC. A bit of cutting to make it fit, but it does the job. There’s no way to tell how this affects the power consumption, because the efficiency of a supply means it can draw less or more current while doing the same job. However, this is MY C200 so IT is under scrutiny.
The C200 knows three power states, indicated by the illuminated power button; Standby (red), on but no video output (orange) and full on (white). When in the ‘white state’, it can vary from idle with the hard drive spinned down, all the way to video playback with network activity and some unzipping on the side. I hooked up my Fluke 87 and DIY current splice adaptera and after examining the power usage in every possible situation, I can safely say it draws between 40 and 44 Watts on average. 40 When doing nothing and 44 when playing a 1080p video with subs enabled. The reason for this relatively small variation in power is thanks to the C200’s dedicated hardware video decoder mentioned earlier. No heavy software processing, so additional energy use is low. Removing the hard drive saves 2W, but then you need to stream all content over the network which cost you 2W as well, and there’s the extra power used but the network router, switch and separate hard drive/NAS, etc. All other power is used for memory, network interface and other electronics. These all stay on at idle, even with the video output turned off.
Because its my main NAS, I need (almost) instant access from anywhere. Standby might be an option, BUT… I left out the C200’s biggest drawback, it doesn’t have wake-on-lan. Yes good folks, the PopcornHour C200 networked media tank with all it’s bells and whistles doesn’t come with a WOL option. This means it always needs to be full on for it to be accessed remotely. There’s no way of getting it out of standby, other then physically pressing the power button. The hard drive spins down after 5 minutes of inactivity, but that just saves you a mere 2W. This pseudo NAS uses 40W when idle, compared to e.g. 8W from a Synology DS212+. It’s the amount I would expect from a PC, not a dedicated media player with HDD.
Let’s talk money. My C200 is up and running 365 days of the year. The few hours it’s down are compensated bij the extra power used while downloading and unzipping new media. Let us assume an average consumption of 42W. That’s 367.9 kWh per year. We pay roughly 22 cents per kWh, so the PopcornHour C200 sets me back 80,94 euros annually. Off course, it’s okay to spend some money to run it to my liking. I’ve downloaded tons of content and watched many hundreds of hours of video directly or streamed from it, but a constant 40W at that price? I have to be able to do better than that.
So what are my alternatives? A dedicated ‘true’ NAS will have faster network access and better power ratings. NAS boxes with the ability to run PLEX media server, like the Synology DS412+, are available as well, but they still don’t pack enough raw power for proper HD transcoding. And I still need something connected to my TV set. Other networked media tank manufacturers like Dune, AC Ryan, Western Digital, et cetera won’t do a significantly better job and PopcornHour is the market leader for a reason. A dedicated media center PC might be a good option. Configurable exactly the way I want it, standby and WOL option and it can replace the PC from part 1 in it’s role as PLEX media server and double als a PLEX client as well. But most of them are not that energy efficient at all. Except for… wait for it… the Mac Mini. There it is again! It can do everything the PopcornHour AND current PMS PC can do and much much more, but with a fraction of the power and it comes with HDMI- and optical audio output. The C200 and PC combined use 91 watts when idle, the Mac Mini just 14W! But 599 euros is still a lot of money…
To summarize. Like The PC from part 1, I’ve got another big power user in among my multi media devices. There’s probably the not-so-orignal power supply to blame to some extent, but I suspect the original PSU doesn’t do a much better job at being energy efficient. And there’s no option to make it go to sleep, let alone wake it up again. Very inefficient indeed! Together, they use a total of around 735 kWh (160 euros) a year just to keep them running. “Need to… stop… buying… Apple gear… argh!”
Optimizing my home’s multimedia capabilities is an ever ongoing quest. The good kind, except for my wallet. It currently consists of a Linksys E4200 v2 with USB connected NAS (Network Attached Storage), PopcornHour C200 with a 1TB internal drive, also configured as a NAS and a windows 7 PC, always on to run Plex Media Server to stream content from the two NAS drives to various (mainly iOS) devices. Both the energy bill and the environment are important issues and I got the feeling all these different devices running non-stop burn up a lot of watts. Ease of use, always being able to connect to my media and watching it in a variety of ways is paramount, but perhaps this can be achieved in a more ‘green’ way to! This blog entry will be the first of many about the power consumption optimization of my personal media systems.
In order to measure the actual power consumption, I treated myself to a Fluke 87 multimeter. Fantastic device. Very accurate and it has the capability to record the measurements to give an average over a long period of time. I constructed a powersocket adapter to splice in the meter to measure the actual current being drawn. This current multiplied by the voltage of the wall socket, in my case 235 volts, gives the wattage (P=V*I).
First up is the Windows 7 PC. Suspectedly a big powerhog. It’s a HP small form factor model with an Intel dualcore 2,7GHz processor. Nothing fancy but fine as a server/transcoder, even at 1080p, which is it’s main purpose. It’s running Plex Media Server (http://www.plexapp.com). For the ones who don’t know Plex, it’s a very powerful and easy to use media indexer, streamer and transcoder for images, music, videos and more. I use it to index music and videos from my two NAS drives, ‘direct play’ the content to my ‘direct play’ capable devices like my Samsung 40D8000 and MacBook Pro, or transcode video for viewing of my iPad, iPhone and systems outside of my locale network.
Transcoding uses a lot of processing power, which translates in overall power consumption. Let’s check that out first. A 1080p video file maxes out the processor and a current of 361 milliamps is being drawn. A simple calculation tells me 85 Watts. Not too bad. I’ve seen systems use up twice that amount, so it’s less then I expected. But 90 percent of the time the PC is idle or streaming without transcoding. It should use significantly less power. Wrong! Doing nothing, it still draws around 218mA. That’s 51 Watts! I’m shocked. A Mac Mini for example (not really fair, because it’s advertised as the most energy efficient system out there) uses only 14W when idle. Assuming the PC will be up and running for about 300 days a year, it’ll cost me around 85 euros annually. Not acceptable at all.
One obvious solution would be turn it off when not in use. But that’s not an option. I’m not a media-snob, but I DO want 24/7 direct access to my media from anywhere in the world. Wake-On-Lan might be the way to go, but bootup just takes too long. I want it quick and snappy! And there are issues with Wake-On-Wan (yes, with a second W) for use over the internet. WOW stability can be dodgy, but more on that later.
Then there is sleep/standby. Not to be confused with hibernate (hibernate writes the RAM to disc and then shuts down. Bootup is faster then a cold start, but still takes a while). Sleep/standby also needs the use of WOL/WOW to gain access to it, but it keeps the data in RAM by powering only the memory and shutting down everything else. Well, not everthing. There’s always some power going to e.g. the NIC. But surely, RAM can’t be that power consuming can it? I put the PC to sleep. 55 Milliamps. That’s still 13 Watts! That’s horrible. It’s basically turned off. Although only a quarter of the power used when idling, it feels wrong to burn away 13 Watts on… nothing.
Just for the sake of experimentation, I measured the currents for hibernate and complete power off. 51 and 50mA respectively… My jaw dropped. Fully shutdown, the thing uses 50mA or 11,75W, for just being connected to a wallsocket. At least the sleep/standby power consumption made sense now. Just 1 extra Watt for fast power on is not a bad deal. To put all in perspective, the current Mac Mini uses 1,16W while asleep and 0,23W when fully shutdown and in both cases, WOL is still fully functional. That’s only 10% of my power hungry PC.
In conclusion, for now, sleep/standby with properly configured WOL and WOW run from my iPhone is the best compromise for (almost) instant 24/7 access with a quarter of the idle power I used to consume. It takes the extra WOL step and about 5 seconds of waking up the PC before I can enjoy my favorite music or movie. I guess that’s doable. Now I’ll just have to restrain myself from running to the Apple store for a Mac Mini.
It can be tricky to get Wake-On-Wan to function reliably. WOL works by broadcasting the ‘magic packet’ across the entire LAN (unless otherwise configured). The NIC with the called on MAC then boots or wakes up the PC. Wake-On-Wan is a bit different. First there’s the need to forward a UDP port, usually 9, to get magic packet from WAN to LAN. But there will be no broadcast, because port forwarding only works to a specific IP address. You have to configure the main router by means of DHCP reservation or ARP (Address Resolution Protocol) to let the router know what MAC address belongs to what static IP while the actual system is not in use. Many people have issues with WOW working fine moments after the PC is shutdown, but after mere minutes to a full hour, WOW just stops working. This is due to the router clearing its ARP table and therefore losing the connection between IP and MAC. By assigning a static IP to your device and manually adding the IP/MAC combination to the DHCP reservation/ARP table, the issue can be resolved. At least, it did for me.