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TBoneMac

macrumors 6502
Original poster
Nov 26, 2017
289
87
CA
Is it bad to downscale resolution on an external monitor - Will this affect performance negatively?

If I have a 1920x1080p monitor connected to my macbook bro and my macbook is in clamshell mode (closed not open so I only have one monitor lit up and working) will games run worse (have lower frame rates) if I downscale the resolution to 1600x900 or lower?

I think I read somewhere that you should never downscale an external monitor from a MacBook Pro and I was just wondering why this might be the case. Please help and let me know if this is true or not and if I should get better frames at lower resolution on an external monitor or not.

I am playing on a 2017 MacBook Pro 15 inch 2.9ghz with 560 Radeon pro. I’m playing Terraria Calamity mod and the frames can go low seemingly randomly (when not much is going on). Sometimes my kernel takes up like 400-500% of my cpu if I look at activity monitor. Should I get a compressed air can to clean the dust?

Sorry for multiple questions but please help.
 

dmccloud

macrumors 68040
Sep 7, 2009
3,007
1,758
Anchorage, AK
There's a difference between downscaling/upscaling and changing the display resolution. When downscaling, the system still renders the video and/or game at the default resolution, but lowers the resolution of what's being sent to the display. On the flip side, many gamers use upscaling instead, which processes the game at a lower resolution then resamples the output for a higher resolution display. This can increase framerates without sacrificing much in terms of image quality.

If you're running the Mac in clamshell mode, I'd recommend running that external display at max resolution. 1920x1080 won't even begin to stress that MacBook or the 560 Pro.
 
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SjoukeW

macrumors member
Jun 8, 2020
62
60
Netherlands
If a Mac runs hot the first sign is kernel process taking a huge amount of cpu.
It is pushing - no operation - instructions to the cpu to do less work and cool down.
I would unscrew the backplate of your laptop and with some compressed air clean the coolers. That might help the most to resolve your problems.
 
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Pakaku

macrumors 68040
Aug 29, 2009
3,170
4,540
I think I read somewhere that you should never downscale an external monitor from a MacBook Pro and I was just wondering why this might be the case. Please help and let me know if this is true or not and if I should get better frames at lower resolution on an external monitor or not.
In terms of graphics, that makes no sense to me whatsoever. Lower resolution means less graphics processing, with the drawback that lower resolutions than native will obviously look blurrier and uglier on a full screen.

If it's a CPU issue instead of graphics, then you're probably bottle-necked by the CPU, and a lower screen resolution probably won't help as much. Terraria is a 2D game, so it's probably not taking as much graphics power anyways.
 
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