An organisation with 25,000 PCs can save $43,000 (£28,800) per year by using power management, according to research by analyst Gartner – but other analysts have called the figures a simplification.
The total power consumption of a well-managed, 2,500-PC organisation is 43 percent lower than for an unmanaged one, according to research by Gartner, which calculated energy use by companies, according to what happened to their PCs after hours – whether they were left running, power-managed, or unplugged.
“Users should look at the power management ability of their PC management tools,” said Federica Troni, principal analyst at Gartner. “If they don’t include power management, they should consider changing their tools or supplementing them with point solutions specifically aimed at power management. ”
While electrical power only amounts to around one percent of the total cost of owning a PC – a much lower proportion than for a server) it is still worth minimising that figure, said Troni. Gartner’s model assumes that employees each have their own PC, and work an eight hour day, 230 days a year – with the PC idle for 30 percent of the time during the day. It set the price of electricity at $0.1 (about 66 pence) per kWh (kilowatt hour).
Well-managed PCs power themselves down overnight, but can be re-activated by management software for tasks like patching and updates. Gartner assumed that half of the hypothetical firm’s notebooks were switched off at night, and half of those were unplugged.
In the unmanaged scenario, users have the option to set up power management, and Gartner guessed that half of users would do this. In the unplugged case, all PCs are unplugged when not in use after hours.
Unplugging the PCs completely would save another $6,500 (£4300) but this would be risky and impractical, since IT departments need access to the PCs out of hours for software updates, said Ms Troni.
Although there are lots of other PC power calculators around, most come from vendors promoting their wares, said Ms Troni. The Gartner calculator will be available to users wanting to work out more specific figures for their company, she said.
The study assumed that 55 percent of employees had notebooks, while the rest had desktops. Ninety percent are expected to use an external monitor, of which half are (still) energy-guzzling CRT screens . “CRTs use almost double the energy of a flat panel display,” said Ms Troni. It assumed that the PCs were on average two to three years old.
“Gartner’s model is flawed in many ways,” said analyst Clive Longbottom of QuoCirca. “I’m all for raising awareness, but I would have though Gartner could do a bit better than this.”
“Models are very easy to get wrong through over-simplification,” said Longbottom, pointing out that a 2,500 employee organisation will likely have less than 2000 PCs, which may be on for more than eight hours a day due to shift workers sharing them – in the contact centre PCs are likely to be in use 100 percent of the time.
“Home workers won’t save the business anything – even if the business gives an electricity payment, lowering it because the business insists that the PC be well managed is a non-starter.2
“Older PCs may not be able to go into as deep a sleep as newer ones,” he said. “They will, however, take more power than newer ones when fully working. New PCs may only take 40-50 W during use – but what about any connected peripherals?”
Gartner has also underestimated the cost of desktop management he warned. “If you are in a relatively unmanaged situation, is it because you don’t already have a good desktop management system in place, in which case it’s going to be a big cost to put this in place (but the possible overall savings in lost business will be huge). If you do already have a desktop management system in place, can it manage EnergyStar settings in the PCs? If not, what can you do? Install agents on every desktop to do this for you? What’s the cost of getting to 2,500 desktops to install something? More than $18 per desktop? What’s the overall payback, then?”
“Your average person knows that allowing a PC to run all the time isn’t as good as allowing it to sleep, which isn’t as good as allowing it to hibernate,” said Longbottom.