The launch of Apple’s latest mobile operating system, iOS 8, caused spikes in internet usage across the UK in its first day, as users rushed to download the 2 gigabyte file shortly after it was released at 6pm on Wednesday evening.

But the morning after, third-party monitoring firms suggest that uptake of the OS hasn’t been as rapid as the company’s previous release, iOS 7.

According to figures from LONAP, the internet exchange point that provides the physical infrastructure for much of England’s internet service providers, downloads peaked at more than 70 gigabits a second at 8pm Wednesday – a 60% increase on the same time the day before.

LONAP’s data on internet usage on Wednesday (red) and Thursday (blue). Photograph: LONAP/The Guardian

The size of the download, which peaked at 2GB for iPad users, also caused trouble for anyone using a device with a smaller capacity. In order for the update to actually install, users had to free up 5GB of space – which is equal around half the user-accessable storage on a 16GB device, and essentially the entirety of the storage on an 8GB phone like the iPhone 5C.

With all music and apps deleted, the update would just about fit, although an easier way for many is to download the file to a PC or Mac, and update the iPhone by syncing with the computer.

But despite the download spikes, uptake for iOS 8 appears slower than the previous version, iOS 7. Analytics firm Fiksu reports that 13 hours after release, the proportion of iOS devices it sees using iOS 8 is the lowest of the last 4 releases. Just 6.6% are using the new operating system, compared to the 15.5% who were using iOS 7 the same period after launch. Even iOS 5, the last update which had to be installed using a computer, had a quicker uptake.

Another analytics firm, Mixpanel, reports similar sluggishness compared to iOS 7, although it shows a higher overall percentage of devices, 12%, on iOS 8.