RX580 + Razer Core X + Macbook Pro Retina 15" 2015 + 2 monitors = laggy
Lately I bought a LG 27UL650 4K monitor and paired it with my 1080P monitor. My Macbook is in clamshell mode right now (so the internal GPU doesn't have to do anything I guess). The 4K monitor is my main one and the 1080p monitor is placed vertically next to it. Lately everything became quite laggy (even browsing in Chrome). Nothing updated at all, just the new monitor.
I ran a test on Final Cut Pro X and I found that running both monitors is maxing out my RX580 processor while playing 4K mp4 files. Before it was very smooth with only my 1080p monitor. So I decided to remove the 4K monitor and only run the 1080p monitor. Processor activity dropped like 30% and all the lag is gone. Reconnected ONLY my 4K monitor and the activity is maxing out again with the same project playing the same files. See image attached for the difference in activity between both monitors.
So my question is, is there something wrong with my setup? Is the 4K monitor really so heavy on my RX580 even when its the only monitor connected? I tried to force it to 1920x1080 with SwitchResX but still maxing out the GPU. Is there some kind of hack I can make my brand new monitor usable again? Browsing the web is acceptable, but video editing is not doable with now. Thinking about using my 1080p monitor for video editing and use the 4K for final touches, but thats about 300 euros down the drain for my new monitor...
If anyone has an idea that would be great, thanks in advance!
Quick update. Tried to edit the same video with Final Cut Pro X on my MacBook screen only (so with the Intel Iris Pro) and it's only at 25% load while the RX 580 is at 100%. Seems quite strange to me that the Intel Iris Pro graphics is running FCPX way better then my EGPU.
Also opening the lid, so with 3 screens iStat menu's is telling me i've get 25/30 more FPS, but its still laggy and the GPU is still maxed out. I can see the processor is running at about 1.3ghz but it's not getting any warmer then 50 degrees celsius. Also this seems kinda strange to me. Looks like the GPU isn't running at full speed.
Your set-up is not the issue.
Apple hasn’t explained their reasoning behind the difference in eGPU performance vs GPU performance in FCPX.
But members here have closely documented similar performance differences.
@mini-i5, Thanks for your reply! That post looks very interesting, will definitely do some testing with different FCPX versions.
However, i'm browsing the web on my Macbook without the EGPU and monitors right now and everything feels so smooth. Nothing is choppy while with the EGPU I get constant stutters. Also my Iris Pro isn't even at 10% load while my EGPU is maxing out every couple seconds doing the same stuff on the web. Suspecting this is causing the stutters.
Could there be anything else wrong? Is it normal behaviour to have my EGPU maxed out with 2 monitors and just a couple of Chrome tabs?
This is a screenshot from the activity a couple of days ago browsing the web:
I don't use Chrome for anything other than 4K YouTube videos - which are decoded by the CPU (IIRC).
Try running the Basemark GPU benchmark for Metal on your eGPU with 4K display attached.
Use High settings.
Let's see how it compares to the average of other RX580 scores.
I have almost the same setup but my MacBook pro 13" is mid-2014. FCPx performance is better without any eGPU at all and working on the small MacBook screen. I used to use the eGPU with a 1080 screen which works fine but the new 4k monitor was really bad. The best way is without the eGPU and external monitor my mac can edit in a breeze. I rather work faster with a smaller screen that wasting time with a large screen... I hope some updates will fix this.