[Help] Run Dual 4k60 on 2015 MBP via TB2 or USB 3.0
I have a 13" 2015 MBP with TB2 and USB 3.0 ports. I want to run dual 4k60 monitors over one TB2 port in a one-stop shop setup.
I've been down the docking station path with StarTech in-depth, and concluded that it's not fully supported over TB2. I was able to achieve dual 4k60 over USB 3.0, but HiDPI was not supported. StarTech told me that this was an implementation issue caused by the fact that the MBP does not interpret the displays as being directly connected when using USB 3.0, and so HiDPI scaling options are unavailable. USB 3.1 might have been capable of driving the needed bandwidth, but my 2015 MBP does not have USB 3.1.
Enter eGPU... I found this community recently and have been reading extensively about the capabilities and workarounds that community members have achieved. I was able to find a similar build by mbp8k where he claimed to have achieved dual 4k60, but I believe it was because he had MST-enabled monitors. Unfortunately, I'm using LG 27UD58-B monitors which don't support MST daisy-chaining.
I have my eyes set on either the Core X 1060 or the Gaming Box RX 580 eGPU's. The most important functionality I need is dual 4k60 with proper scaling to run smoothly for daily use. Secondarily to that, I'd like to run WoW, Civ 6, and other low-demand games on one 4k monitor at a reasonable resolution. I don't run Bootcamp but am willing to consider it for the extra frame rates if the community scripts are easy enough to implement.
- Can you confirm if it's possible to achieve dual 4k60 with HiDPI scaling & smooth performance over one TB2 port?
- If not, is there an eGPU that can take advantage of two TB2 ports simultaneously?
- Any setbacks, gotchas, or customizations I should be aware of?
- Any specific chassis/card recommendations beyond what I mentioned above?
I have a 13" MacBookPro 2015 and I can attach a least four 4k Displays with my eGPU, of course over TB2.
You should read the builds at his site first, e.g. https://egpu.io/forums/builds/early-2015-13-macbook-pro-gtx1080ti-11gb16gbps-tb2-asus-xg-station-pro-via-tb3-tb2-adapter-macos-10-13-6-oliverb/
Who connects displays with USB3? I didn't know this was even possible and for sure it can't be of any good. And USB3.1 doesn't mean higher bandwidth, it's USB3.1 Gen 2. I have USB3.1 Gen 2 on my 13" MBP 2015 -with help of the eGPU enclosure.
Hey OliverB thanks for the reply. I already stumbled across your build before posting. I wanted additional confirmation as your build only confirmed running one 2k60 resolution monitor over TB2, whereas I need 8k60 (2 x 3840x2160). I didn't see any any builds that fit my description.
I agree that running over USB3 sounded crazy. The idea came from StarTech's DK30A2DH docking station. I chatted and spoke with them on the phone and ultimately concluded that it would probably not work, at least not smoothly. They claim that macOS needs to detect the display(s) as being directly connected to the TB bus in order for HiDPI scaling to work. So in this USB3 dock's case, macOS would not detect a direct connection (the dock would be detected as a "middle man"), thus HiDPI scaling would not work. This caused me the same issues that are illustrated here.
Your post sounds promising. Just to be clear, when you run multiple 4k monitors over TB2, do you have any issues aside from having to hot-plug after login? DPI scaling works correctly? No tearing, artifacts, or spontaneous disconnects?
Thanks for the concise answer @mac_editor! Also, thanks for all the work you've done for this community; I've seen your GitHub work and it is phenomenal.
I'm looking for an eGPU that's a one-stop shop for peripherals (USB, Ethernet, etc.). The Core X2 looked promising but is out of budget. The HP Omen Accelerator fits the bill, but I'm worried about a specific comment in the eGPU.io review:
Last but not least, the expansion ports may not have full compatibility through the Apple USB-C/Thunderbolt 3 to Thunderbolt adapter for older Macs.
I wasn't able to find a build in which someone confirmed or denied the expansion ports having issues over the TB adapter.
@iscsica Unfortunately I have not tried enclosures with extra ports on a TB2 machine (I now have a TB3 machine). Now don't take my word, but I think it works on macOS but not bootcamp Windows. Perhaps @itsage may have more insight on this matter. One other thing to add: Displayport IMO works better for higher resolutions (4K60) on macOS. Also, go for AMD if the primary purpose is multi-monitor. Much easier setup and compatibility.
@mac_editor I totally agree with all of your points. I pulled the trigger on the Omen Accelerator and the RX 580 (Gigabyte). I found a steal on Newegg that includes 2 AAA games with the 580. Also the Omen is going for $230 right now. Grand total $440. (Not bad for all that real estate)!
I'm happy to try setting up Bootcamp when I get some free time. I can report back results for both macOS and Windows regarding the expansion ports working over TB2. Stay tuned!
@iscsica, I may have only one 2,5k@60 monitor running in my build, but there are still 3 Displayports left in the GPU. The GPU works in full functionality over Thunderbolt (2/3), it's essentially the same as built-in a Desktop Tower.
So, you can plug as many monitors to the GPU as the GPU can generally do. And a nVidia Geforce GTX1080Ti can do a lot.
Don't underestimate the "hot-plugging" problem with the 13-inch MPB 2015 under Bootcamp. It's really quite difficult, I need mostly 2 or 3 tries, sometimes even more.
But once your system is running with the eGPU, it totally pluggable, on-off as often as you want.
@mac_editor @OliverB . Just checking in. Wanted to confirm that all of the expansion ports, including USB and Ethernet, all work flawlessly over TB2 in macOS. I've yet to setup Bootcamp so I can't confirm for Windows yet. Thanks both for the guidance.
@mac_editor @OliverB , I forgot to mentioned that the 2015 TB2 MBP does not work in clamshell mode. All peripherals and chassis LED's turn off and the GPU winds down. They immediately come up if the MBP screen is opened. The primary display is set to one of the external monitors. Can either of you attest?