I’ve had my Retina Macbook Pro for just over 3 months now, and during this time, it’s both impressed me and pleased me with it’s performance, good looks and battery life. The other day I was reading up on the Apple support webpages for an unrelated problem, when I stumbled over a thread relating to poor battery life on the Retina Macs. Interested I wondered what issues other people were having, and discovered that it seemed to be a widespread problem. Many users reported that they were seeing only 3 or 4 hours battery life after full charge, when the quoted figure is 7 or 8 hours easily. It hit me like a train: I’ve never seen battery life anywhere near as high. Coming from an old Macbook Pro (circa 2008) I was impressed because comparatively my new Retina was miles ahead, but those 3 and 4 hour estimates set alarm bells ringing – did I have a shitty battery mac?
Luckily the support site had a couple of tips: zapping the PRAM was one of them, and secondly to kill off a corrupt desktop process. I quickly bookmarked the pages for later reading, and set an alarm to follow up. Back at home I ensured my Retina was fully charged – with the battery showing 100percent, I unplugged to go onto battery power and watched the power meter. After a few minutes saying “calculating remaining time”, I got my figure – 3.5 hours!!! To say I was dismayed was an understatement. You don’t expect your £2 Grand pride and joy to have lost battery condition so quickly. I followed up the bookmarks, and proceeded to zap my pram and wipe out the faulty process: improvement, we were now seeing 4.5 hours, but then witnessed this quickly fall rapidly down in 10 minute increments.
By now, this was really worrying me. Having bought the Retina in Canada worries regarding warranty started to surface. Where was all this battery going? A glass of wine, and some thinking time followed. I checked the activity monitor, but no processes were consuming huge chunks of CPU time… Back to the basics, Layer 1: Physical, with virtually no applications running, the bottom of the machine was hot. Checked a quick schematic of the machine, and the place that was the hottest was definitely where the CPU resided. So how can CPU be running hard but no process consuming any CPU time? Closed every application (even though only had Bit torrent, iTunes, Mail and Chrome open). I could feel the machine physically cool, and the battery life start creeping up, 4 hours, 4hrs 20, 5 hours, 5 hrs 30. So an application was causing crippling battery life. In the past I’ve known iTunes to be a resource hog, so opened it on it’s own and started playing music: battery life stuck at 6hrs 25 minutes (on 75 percent battery) with no noticeable drop. Opened Mail, again no noticeable drop, uTorrent is lightweight so no surprises, opened it and again no noticeable drop (even when hitting 1.5MB a sec). Opened Chrome: BANG! battery started to drop like a stone!.
So what’s going on here? Chrome is draining the battery – I proved this by only having Chrome open. Chrome closed: battery 6hrs 25, Chrome open for 5 minutes – battery showing 3 hrs 20 and machine running hot.
I can only assume that the current build of Chrome supporting Retina display is a bit of a resource hog. I’d speculate that the fact that each tab runs a process taking 2.5- 3 % CPU quickly adds up and makes the machine run hot. Certainly I’ve got 4 cores of Ivy Bridge at 2.6Ghz. I’ve switched over to Safari, and done several tests – I can drain 20 percent battery using Chrome for half an hour, whereas using exactly the same sites in Safari barely dents battery life. I’m not sure this is a problem that anyone else has had, but certainly for me I’ve checked this both on a 2012 Retina Macbook Pro (2.6Ghz) and a 2012 Macbook Air with similar results. If anyone has any ideas as to what is causing this, or if they have had simliar problems I’d be interested to hear from you.