Huge gaming difference in eGPU performance between restarts (XFX AMD580, 2018 Ma...
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Huge gaming difference in eGPU performance between restarts (XFX AMD580, 2018 MacMini running Win7)  


Eminent Member
Joined: 2 years ago


Two days ago I played the old 2016 Hitman game (via Epic Games store... not sure if this can make a difference?). To my own surprise, performance was really great, and at 2540x1440 resolution I was able to select the games' highest graphics settings: Level of detail, Texture quality. Shadow Maps, etc.... all pretty much maxed out, and performance was great. Very smooth an detailed.

I then rebooted into Mac mode for work. And yesterday evening another reboot in Win7 mode. Same procedure as always:
EFI Boot usb stick –> turn on Mac --> wait for Boot screen --> plug in eGPU --> select EFI boot --> hope Win boots (it sometimes freezes) --> start Epic Games launcher --> launch Hitman

To my own surprise, this time around performance was complete rubbish. Even at 1920x1080 resolution, it's not smooth at all. 5min of playing and I'd get a headache. (I'm a casual gamer, so may not be able to word this properly, but I think "low frame rate" is the right way of describing it). If I had to put a number on it, I'd say performance was 30% of what it was the day before.
Besides: the game won't allow me to select high settings, so at 1920 I was restricted to low texture quality, medium shadow maps, etc... 

Tried restarting a few times... problem persists. As if that first-time experience from 2 days ago was pure luck.

One thing I noticed was: the first startup AFTER the "great performance" experience caused the eGPU's fans to steam up for 1s. (It sometimes, though very rarely, does that during a startup or just before an unexpected MacOS crash/shutdown. Don't know why.)

Graphics Card is an XFX AMD580; Akitio Node Pro enclosure


  • same cable
  • same screens (Screen1: Displayport to eGPU; Screen2: USB-C to MacMini)
  • same Windows 10 version (as described in several builds), never ran any updates
  • same AMD Radeon software (it offers an update – is this advisable?)

because the boot success is a bit hit and miss, I sometimes try various approaches:

  • sometimes I connect the eGPU before powering up, sometimes after I can see the EFI boot stick
  • sometimes I keep Screen1 connected via 2 cables (Displayport to eGPU and HDMI to MacMini), so Windows recognised that screen twice before I disconnect the HDMI cable. Problem is: Although I have that secondary screen connected to the MacMini via USB-C, it's hit and miss which of my 2 screens shows the disk selection during startup. And if I only have the USB-C screen connected to the Mac, it sometimes stays black... so I can't see the Apple Logo or startup disk selection
  • at some point I had my video projector attached to the eGPU's HDMI port (whilst the Screen was simultaneously attached to the Displayport). This was during the "great performance" boot, and right before the first "bad performance" reboot when the AMD card's fans spun up).

Can someone please help? Do I need to do some manual purge? (I remember days when the eGPU didn't work, and physically removing/re-installing it from the enclosure did the trick).

Could it be that EpicGames launcher (worst launcher ever, doesn't even recognise external HD for games sometimes) launches games in 16-bit mode rather than 32bit?
Should I update the AMD Radeon software? (I hope not – took me forever to get a semi-reliable Win7 partition running that recognises the eGPU... never change a running system).

Thank you very much!

2018 MacMini i7 / Mac OS Mojave / 4k iiyama screen

Active Member
Joined: 3 months ago

some ideas you can try to solve your problem:


  • Try updating to Windows 10 20H2. I personally had great success with that version on my 2018 MacBook Pro. I don't require any fancy tricks or bootcamp drivers on that version of Windows 10.
  • Does your RX 580 work in MacOS? XFX Cards are known to cause issues on Macs. Maybe these issues translate to Windows as well.
  • Running some Benchmarks could be useful to compare your performance to similar setups. This way you might be able to quantify the performance loss.
  • It might sound obvious, but have you double checked that you are not accidently using the internal GPU?





2018 13" MacBook Pro [8th,4C,U] + RX 580 @ 32Gbps-TB3 (Mantiz Saturn Pro) + macOS 11.1 & Win10 20H2 // quiet mods [build link]  

Eminent Member
Joined: 2 years ago

@top_tim, yes, the XFX is working fine with MacOS and Windows.And yes, I did double-check that I'm not accidentally using the internal GPU. 

I got things to work again yesterday. Not sure what solved the problem, but: I removed the AMD card from the enclosure and put it back in, then rebooted. The first two reboots were weird: EFI Boot recognised the eGPU, but Windows didn't (screen stayed black whilst my 2nd screen had a picture). So I moved the cable to a different Displayport slot on the card. That worked. Game was running perfectly smooth at high res & highest settings. Wonder what the next restart will bring... (currently in MacOS).

eGPU behaviour really is hit and miss with this current setup. Could be the XFX card, could be Mac OS (still on Mojave for several reasons):
Generally, I need to keep the eGPU enclosure switched on. When I turn off the Mac, it turns off automatically. Then for the next day's reboot, I boot MacOS and once I see the Finder I plug in the TB3 cable which turns on the card.

I once tried to power off the enclosure properly (power supply switch), but that caused problems on next reboot. (From what I remember, I had to physically remove the card from the enclosure and put it back in). Ever since then I don't touch the enclosure's power supply switch.

I generally don't believe in black magic and I'm not superstitious – but thus eGPU journey has taught me otherwise 😉


2018 MacMini i7 / Mac OS Mojave / 4k iiyama screen

New Member
Joined: 3 months ago

@macbowtie, Can you share a few benchmarks? I am running a similar setup, just with a rx-5500-xt... Maybe it can help to compare...



2015 15" MacBookPro11,5 | Radeon RX 5500 XT 8GB | Asus XG-Station-PRO | Win 10 (2004) | MacOS Big Sur 11.1

Eminent Member
Joined: 2 years ago

@itsmedom, sure. Any suggestions for benchmark tools for Win and Mac?

(Could be a few days before I go into 'gaming mode' and boot up Win again).


2018 MacMini i7 / Mac OS Mojave / 4k iiyama screen

Noble Member
Joined: 4 years ago

There is a bandwidth change in macOS between connecting before boot and connecting after boot. I didn't test any games though.


Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case