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  


New Member
Joined: 10 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]  

aurelius pontius, Ningauble77, nando4 and 1 people liked
New Member
Joined: 3 months ago

@wiredachilles, Is error 12 specific to AMD GPU? I have a tb3 laptop and want to use egpu with that. Also was planning on using the same egpu enclosure for desktop. Planning to buy the same mobo and use egpu against both laptop and desktop. Will be using nvidia's 2080 super and windows 10 on both laptop and desktop.


To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.


New Member
Joined: 10 months ago

@raghuveer_pai_mangalore, If you search around this forum a bit, you'll see that error 12 is a common issue with Windows and the TB3 protocol. If I recall correctly, it's an error caused by Windows' inability to appropriately assess how much voltage is being sent via TB3 to the device and the OS believes it's not sending a sufficient amount to the device. 

With that in mind, I can't say for certain if you'll observe error 12 with an Nvidia card inside of an eGPU enclosure, but I don't believe this issue is unique to AMD GPUs. In the thread I link in my write-up, the poster did try with an Nvidia card initially, but it didn't work out of the box. In their case, the Nvidia card produced error 43 instead of error 12. However, they had an AMD processor (mine is Intel).

A few builds have been posted very recently with a laptop and an Nvidia 2080 Super in an eGPU enclosure which, according to the write-ups, just seemed to work after the drivers were installed. Here's the links for your convenience:

From these write-ups, configuring the eGPU with a Windows laptop and the aforementioned Nvidia card seems relatively painless in comparison to what I had to do. This bodes well for your plans, but maybe ask the posters of the above builds if they had any issues they didn't mention. 

On another note to those who pass by this build in the future (I posted this 6 months ago), I've had virtually no issues with stability in my setup. Windows updates didn't disrupt my ability to use the eGPU, and I no longer needed to swap out the pci.sys file with Windows updates either. For AMD driver updates, this did break the eGPU initially, but that's because the driver installation needs to uninstall the previous drivers before they install themselves. After installing the latest drivers, my card was detected inside of the eGPU and performance continued without any issue. 

I've never experienced any crashes, no issues with CPU overheat or issues with GPU overheat. Obviously there's a performance hit using an eGPU, but that's a known tradeoff for form factor and slightly more "portability".


This post was modified 3 months ago
2020 ASRock Z490 Phantom Gaming-ITX/TB3 [10th,6C,K] + RX 5700 XT @ 32Gbps-TB3 (Razer Core X Chroma) + Win10 2004 [build link]  

New Member
Joined: 3 months ago

@wiredachilles, This is super helpful. I'll go through the builds. Thanks


To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.