What is slowing down my m5 2016 MacBook on the Ultrafine 4K monitor?

Discussion in 'MacBook' started by j.quintana, Jan 27, 2017.

  1. j.quintana macrumors member

    Oct 2, 2015
    When I hook up my m5 2016 MacBook to my recently purchased Ultrafine 4K monitor it gets kind of slow. There is no lag with the keyboard or the mouse, but using Firefox for example gets much slower than with just using the MacBook without the 4K monitor. When I open Firefox I have three tabs open as default and it takes a lot more time to load these websites.

    I can not see the reason for that behaviour because when I look at the CPU usage while Firefox takes its time it looks like this:


    This doesn't look like the MacBook is overchallenged. More than 90% of the CPU usage is caused by a process called "Firefox Web Content" but still there is a lot of CPU power that isn't used at all. So what is the bottleneck here? Would it be much faster with a MacBook Pro? I'm seriously thinking of upgrading but I don't want to be disappointed. Most benchmarks say that the MBP is "only" 50-100% faster than the rMB which is a lot for sure but sounds like Firefox would still take 10 seconds for opening a new window and loading the three default tabs instead of 20 seconds on the rMB and I would still call that slow...
  2. andy9l macrumors 68000

    Aug 31, 2009
    England, UK
    FWIW I found my rMB almost unusable when connected to my 4K display, too. It's fine for basic browsing in Safari, but anything slightly taxing starts to show the limitations of these little machines.

    I'm reluctantly upgrading to a 13" TB MBP. I loved my rMB.

Share This Page