2020 ASRock Z490 Phantom Gaming-ITX/TB3 [10th,6C,K] + RX 5700 XT @ 32Gbps-TB3 (R...
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2020 ASRock Z490 Phantom Gaming-ITX/TB3 [10th,6C,K] + RX 5700 XT @ 32Gbps-TB3 (Razer Core X Chroma) + Win10 2004  


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Joined: 5 months ago

System Specs

Inwin Chopin Chassis

Intel Core i5 10600K

ASRock Z490 Phantom Gaming-ITX/TB3 motherboard

Noctua NH-L9i Fan

32GB (2x16GB) DDR4 2400 RAM

1TB Intel 660P M.2 SSD

eGPU Hardware

Razer Core X Chroma  + AMD Radeon RX 5700 XT

Installation Steps

I started with (and still have) Windows 10 update 2004 formatted onto a new SSD (no prior Windows installation). 

After installing Windows, I then did the following:

  1. Install Thunderbolt support software from ASRock support page (version
  2. In BIOS/UEFI panel (hold F2 during boot), disable CSM ("4G Decoding" was enabled by default for me, check to make sure this setting is also enabled on yours)
  3. Restart PC with eGPU plugged into TB3 port, "Allow All" in Thunderbolt console to all instances of the  Razer Core X Chroma chassis (this will prompt Razer Synapse activity too, which you can ignore)
  4. Confirm that graphics card is recognised in Device Manager, but is producing Error 12
  5. If card is recognised, install the relevant AMD drivers (I installed Adrenalin 2020 Edition 20.4.2, but these drivers will probably be updated in the future)
  6. Replace current build pci.sys with pci.sys from update 1903 using Safe Mode to write to drivers directory (keep a backup of both versions on the disk, I kept mine in the same directory as pci.sys for convenience after a Windows update)
  7. Launch into with eGPU plugged in, verify that it works using Device Manager

In my case, as I've no dGPU aside from the one in the processor, I could verify that it worked without going to Device Manager due to the AMD XConnect Software popping up on my desktop during boot. 

Windows updates will break the eGPU (you'll get error 12 again). To fix this, I just re-did step 6 from above. When launching into Windows from Safe Boot, it immediately recognised the eGPU again and I could continue as normal.

This forum has stickied instructions to get pci.sys from an older version of Windows (specifically 1903). For convenience, I followed the process detailed here to get the drivers necessary for step 6.


All benchmarks were done by forcing the benchmark executable to use the eGPU via Windows' "Graphics Settings" menu, and were performed on an LG 4k monitor using an HDMI cable plugged directly into the back of the graphics card. 

I also did the benchmark on the dGPU in the processor for base-lining and giggles. The results on the eGPU were obviously better. I ran the Superposition benchmark twice on the eGPU, once on Extreme and once on Medium:



 Unigine Heaven



Superposition Benchmark v1.1 4362 1593633918
Superposition Benchmark v1.1 13616 1593634384
Superposition Benchmark v1.1 271 1593633563


I was inspired to build this PC by this post, among many others on this forum. Shout outs to @Ningauble77, their write-up was extremely helpful. 

My main PCs are a 2019 Mac Mini and a 2012 MacBook Pro. I need OSX for my job because I work with iOS applications frequently and require XCode, but had thought I could have a multi-functional computer by using an eGPU with my Mac Mini. With this in mind, I got an eGPU and corresponding enclosure based on Apple's recommendations to save my self some admin work, and then realised that many of the games I want to play don't actually work on Mac. 😕 

I tried for a few weeks to get the eGPU working with bootcamp, but eventually gave up and decided to build a Windows PC. As I already had an eGPU working on my Mac, some games installed, and I live in a tiny flat with limited space, I figured I would get a small form-factor PC and swap the eGPU between OSX and Windows. On that note, I'm really impressed by the In Win Chopin case. It's great how much you can fit in such a small case. The specs on my Windows PC are much better than those of my OSX PC, and the form factor isn't too different, though the Mac Mini is clearly smaller. 

The main improvement for me is that I can actually run games that are exclusive to Windows. I love the Command and Conquer franchise, but the few of them that were ported to OSX are 32 bit and don't work on Catalina. There aren't any Command and Conquer games at the moment that require an eGPU to run, but there are other more recent RTS games I can play now that don't work on Catalina (e.g. Homeworld). 

Thanks again to everyone in this forum for help. I hope this guide can help other people. This is my first time posting, so, if I forgot to add something, I'll do my best to answer any followup questions that people have. 

2020 ASRock Z490 Phantom Gaming-ITX/TB3 [10th,6C,K] + RX 5700 XT @ 32Gbps-TB3 (Razer Core X Chroma) + Win10 2004 [build link]