Ever since I upgraded my iphone 5c from iOS 7 to iOS 8, it was running very low on memory. I kept getting the low memory warning after taking 3-4 pictures. I deleted all the apps on the phone (except google maps), removed all the photos, music and video, and I still couldn’t get more than 300-400Mb. The phone was basically unusable. I knew iOS 8 had a larger memory footprint than iOS 7, but I didn’t expect it would be usuable on a 8GB phone. Especially iPhone 6 has just been released, so an iPhone 5 wasn’t that old!
I wanted to downgrade back to iOS7, but I was a day too late. Apple stopped signing iOS 7 on 29 Sept. Also jailbreaking wasn’t available for iOS 8 at the time. I was stuck with a more or less useless smart phone.
Then my 16GB iPad mini was also starting to run out of memory. However I had 1GB of photos synced from my old mac, so my first thought was to remove the photos. However, I no longer had the mac, and I couldn’t remove the photos with my windows iTunes installation. My only option was to reset my iPad mini.
With a fresh new installation of iOS 8, I noticed I had 11GB free on the iPad. It occurred to me immediately that I should have have a lot more memory on my phone instead of the 400MB I was struggling on. And indeed, after resetting the phone, I suddenly had 4GB.
I still don’t know what was eating up all the memory on my iDevices. (The lost memory wasn’t listed under Settings -> Usage). I am blaming the iOS 7 to iOS 8 upgrade being very poor, leaving a lot of temporary files behind on the devices.