Standby vs Shutdown
When we talk about a lower power state, there are only two options we would recommend, either PC standby (incl hybrid sleep in Vista) or a complete shutdown.
When we talk about PC standby, we mean the inherent power management capabilities of windows operating systems to place monitors, hard-drives and the PC into a sleep mode after a period of inactivity. This can be achieved my modifying the windows power settings and can be managed centrally by systems administrators using group policy with admin plugins such as Energy Star’s EZGPO tool.
Shut down solutions turn the machine off completely. This can be done manually by Start > Turn Off Computer or managed centrally through PC Power Management tools such as NightWatchman from 1E. In order to turn off PC’s remotely you need to deploy power management software and cannot do this through group policy.
Why bother going the whole way?
Many organisations that we talk to have adopted a PC standby based approach. When this approach is implemented, it does compromise the delivery of the service. Not only from an end user perspective but also the ability of the IT department to manage and patch the distributed computing environment. However, the purpose of this discussion is not to look at the technical merits of either solution, but rather the financial benefits.
Machines in standby are still drawing energy, in some instances a significant amount whereas machines that are shutdown are only powering the wake on lan component of the network card, usually under 2 watts. So how much do machines draw in PC standby?
Modern processors and monitors are increasingly efficient in standby, as is the Vista operating system. A new configuration is usually drawing between 5 and 10 watts in standby. Older machines however, running XP are less efficient and we have instances where our energy meter recorded usage in excess of 40 watts in standby for a Pentium IV running XP.
Anecdotally, it also appears that the longer a machine is in use, the more energy it tends to use in standby. This is true of all operating systems and we suspect it may be due to the registry growing as more and more applications are loaded. If you have the tools, as a simple test, take a new configuration and test the power in standby. Then take an identical machine that has been with an end user for a few months and do the same test. You will be amazed at the results.
Every Watt Counts
Dell placed energy meters on the machines that they were putting into standby and realized that they could save an additional 5 watts per machine if they could shut the machines down completely. By deploying 1E’s NightWatchman solution they achieved exactly that, actually delivering a better service to the end user due to the robust nature of the solution implemented.
To invest in power management tooling to save an additional 5+ watts on face value seems ridiculous and to some degree it is, there are many other benefits not covered in this paper. However, when you extrapolate 5 watts out, the findings are pretty startling.
5 watts in standby actually equates to 43.8 kWh per annum. Not too startling in itself, however what does that cost us? In South Africa, at current average rates you will pay around R22 per annum per machine for that inefficiency. Multiply this by 1000’s and the numbers start to add up. Now add the impending increases and you are looking at closer to R30 per machine.
If you are not getting the picture yet, here is another staggering scenario. Under the Power Conservation Programme, business will be targeted with energy savings and those that fail may pay as much as R18 per kWh. In this scenario, every watt does actually count! The 5 watts in standby that you are ignoring could cost you R788 per annum per PC. It may also be the additional saving that your business requires to meet targets so don’t be complacent, eek out every bit of power saving that you can get your hands on.