MB 2017 Clamshell users - any lag/issues?

[SethBoy]

I have a 2017 1.4 GHz i7 MacBook with 16GB of RAM, and I was considering getting a USB C 4K display and use my MacBook as a desktop at home.

I have a 2017 3.0GHz i5 iMac in the office and it feels like it’s somehow snappier than my MacBook. Obviously, that’s probably because it is a much beefier machine. My worry is that the MacBook is going to feel even more sluggish having to drive a 4K display.

Anyone using a similar setup and can sense if there is any performance difference between using the MacBook as is versus in clamshell mode with a 4K display? Thanks!

 

[casperes1996]

With a 4k display (and the internal display disabled) the MacBook will have to run around 60% more pixels. The CPU won't really get that much extra work as a result of more pixels; However, the GPU will. As long as you don't expect to do anything in particular with the GPU whilst running the 4k display, performance shouldn't be much different to running the internal display only.

The thing is; What is it that you think feels more sluggish on the MB versus the iMac? Because if it's something relating to CPU speed, the MacBook won't get any slower than it is. If it's visuals, like animations or whatnot, it may reduce the speed a bit, though the more pixels is only going to put more stress on certain parts of the GPU and other parts of it won't really be pushed that much harder.

Anyway, all this is theoretical and I have no practical experience myself. Just wanted to chime in in case it was helpful anyway. Hope someone with actual experience can help you even more

 

[ravipiero]

I've been using my 2017 i5 8gb MacBook with 34" LG 34UC99 for few days now. My notes:
- setup is very easy, a single usb c cable can power the macbook and run the display full resolution 60hz
- to my surprise, the performance is as good as without the external monitor. My use case is few safari windows, itunes, twitter, and netbeans always open. No lag / slow down at all
- I purchased the monitor because I was getting a good deal, and my plan was to purchase next gen 15" MBP to go with it. But now I might seriously considering next gen 12" rMB

 

[ZapNZs]

Mine runs a crap ton hotter with a 4k display and did have noticeable lag. The lag I noticed may be more attributable to it being a 30hz refresh rate than due to the GPU.

 

[SethBoy]

Thanks for the input guys.

I have tried out the 4K LG display at the Apple Store and found the performance to be passable. Most things are smooth, but animations for Mission Control tend to be sluggish when first invoked (and then thereafter being smooth). Then again, this is also the case even when the MacBook’s native display is being used on its own. I’m still on Sierra, so I’m not sure if this has been fixed in High Sierra.

Aside from that, it can get pretty warm playing HTML5 1080p videos. I also get a notification that performance is reduced because of it. Enlarging YouTube videos to full screen has a lot of animation stutters too.
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Mine runs a crap ton hotter with a 4k display and did have noticeable lag. The lag I noticed may be more attributable to it being a 30hz refresh rate than due to the GPU.

You should really use USB C for 60Hz. I get 30Hz via HDMI and it’s horrible.

 

[EugW]

Thanks for the input guys.

I have tried out the 4K LG display at the Apple Store and found the performance to be passable. Most things are smooth, but animations for Mission Control tend to be sluggish when first invoked (and then thereafter being smooth). Then again, this is also the case even when the MacBook’s native display is being used on its own. I’m still on Sierra, so I’m not sure if this has been fixed in High Sierra.

Note that High Sierra brings Metal 2.

https://www.laptopmag.com/articles/mac-os-high-sierra-preview

Take the Mission Control window that shows all of your open apps. Before I upgraded a 2016 13-inch MacBook Pro to High Sierra, I noticed lag when I would try to pop into this view. Now the animation is silky smooth, even when I have more than a dozen apps open. But you won’t see the full benefit until Metal 2 apps start popping up in the App Store, which will likely be in the fall when the full version of High Sierra arrives.

How does apply to running an external 4K monitor? I have no idea, but I bring this up because Sierra isn't a good surrogate when assessing graphics performance of High Sierra.

 

[Bbbean]

I’m planning on purchasing a 2017 MacBook and connecting it to a 1440p monitor using the HDMI port on the Apple USB-C digital AV port. Can I expect 60Hz refresh rate and should I expect any major differences in performance? It’s a great machine that fits my needs but i’m worried about the performance when connected to an external monitor as I need to frequenty for work. Thanks.