Recommended: 32 GB or more of free space on a solid-state drive (SSD) A multithreaded 2-core CPU will have four threads available for processing, while a multithreaded 6-core CPU will have 12 threads available for processing. Simultaneous multithreading, or hyperthreading, of CPUs typically features two threads per core. The problems appear to be mainly limited to notebooks running OS X Yosemite.Minimum: 2 cores, simultaneous multithreading While complaints of user interface lag have resurfaced following Apple's release of the 2015 MacBook Pro, similar issues have been reported in the Apple Support Communities, Reddit, Stack Exchange and MacRumors discussion forums by owners of 13' and 15' mid-2012 through mid-2014 Retina MacBook Pro models. My old 2010 Macbook Pro 13' doesn't lag this bad on Yosemite.' 'This is the most significant lag I've experienced on any laptop on Yosemite. 'I know that Retina displays are taxing on GPUs, but the Intel 6000 series seems incapable of driving this display without extreme choppiness in Yosemite for a number of actions- Mission Control, switching between windows, opening new windows, etc,' reads a post in the MacRumors forums. But the issues persist for some, with MacRumors forum member 'cookies!' claiming that his 2015 MacBook Pro has 'the most significant lag' of 'any laptop on Yosemite' he's ever used.

It is also recommended that affected users perform a clean installation of OS X Yosemite to ensure that the issues are not the result of restoring from a backup. It is worth noting that new Macs may experience slower performance after booting up for the first few times as the computer indexes.

' 2015 rMBP problems: 5-6 hours of battery life & major UI lag' posted by Youhoney.

' 2015 Macbook Pro's Intel Iris 6100 is so choppy in Yosemite' posted by cookies!.

One potential solution involves resetting the Mac's PRAM, while temporary workarounds listed include increasing contrast and reducing transparency under the Accessibility menu in System Preferences. A pair of threads related to the issue have received close to 200 replies and 20,000 views within the discussion forums, with some users that previously experienced UI lag offering advice on how to resolve the problem.

Macbook pro user guide 2012