Four PCIe slots into the Razer Core v2???
@lefuturdelavenir, Incredible work! Looking forward to seeing your test with different cards.
Ok, I've receive some PCIe x16 risers "mining style". The idea is to try using multiple GPUs at the same time and also evaluate how the positioning of the GPU affect the overall performance.
Note: I'm no hardcore gamer so raw performance is not crucial to me. I'm more looking for the best performance versus power consumption (and noise) ratio.
First try is to plug the RX 560 in addition to the RX 570 present in the CORE. As a result, both GPUs are detected by macOS. According to System Report, the RX 570 use 8GT/s x4 and RX 560 use 8GT/s x1.
I don't have multiple monitor so I just launch Geekbench 5 on each card. The RX 570 scored at 33080 and the RX 560... well I couldn't get the result: I have a nice "We're sorry, but something went wrong" message even if the benchmark seems to run ok. When searching the last results online, I've found a score of 1. Seems I've broke Geekbench :'( Sorry.
When switching my monitor from one card to the other everything looks fine. Is apparently just a bug with Geekbench.
Now to the next test. I've unplugged the RX 570, only leaving the RX 560 in the x1 slot. A this time, the main PCIe slot in the CORE is empty. The RX 560 only use x1 and works great. It's actually difficult to feel the difference with the RX 570 in the main slot. The UI feels good, browsing and 4k playback in YouTube works as expected. Geekbench scored 16105.
- In conclusion:
- Well, it works !
- The PCIe speed is indeed 8GT/s when plugged directly to the thunderbolt controller. That could benefit to my USB ASM1061 controller eventually, thought I only use USB 2.0 so... not so interesting anyway.
- Multiple GPU is possible thought daisy chaining and x1 link, with some performance penalty.
- I think I'll consider removing the PCIe switch. It implies designing a triple PCIe x1 daughter board PCB.
Quick update. I've design a custom daughter board to replace the original one.
I've just installed the daughter board for now. I still use the PCIe switch. First tests are going well for now, everything is working.
It's better looking that the "wood style" prototype I've previously used 😀
I placed dual USB receptacle at the same position that the original, with USB headers similar that those presents on motherboards. Seems I nailed the positioning of USB connectors and PCB holes: now I can screw the board like the original.
One big mistake : I've placed the Ethernet connector in the wrong way : it's faced inward I can be pretty stupid some times! I realized the mistake 30 minutes after the PCB order went to production... I'll do better next time.
Now I have to build a USB cable to feed the USB headers.
I also have to replace the PCIe board I use, the one with the PCIe switch, with the one you can see on the first picture. I've designed this board so that 3 PCIe modules are the exact same size than the board I currently use. So I don't have do redo the wood circuit holder.
I hope I'll find some time to work on that this weekend.
I have build a USB cable to feed the USB headers and replace the PCIe board, finally putting an end to the PCIe switch. Pictures will follow.
Now every boards are managed directly by the thunderbolt controller, but... there is a small problem: the ethernet card doesn't work anymore. I've switched the card and it turns out the intel i210 PCIe simply doesn't work in that configuration. It's simply not recognized and don't show up in macOS. I have four PCIe ethernet cards on hand and none works except the i350-t2 (that barely fit, but it fit!). I've realize that every card that does not work is PCIe 2,5GT/s. At 5GT/s it works, like the i350. I've tried 8GT/s successfully in the past.
That's quite interesting to me. I have no idea why it's not working.
Anyway. Now that I know it's working*ish. Here are two other designs I had done but not orderd.
This is similar to the one I use but has a PCIe link available from the outside of the case via a USB3 connector on the rear pannel. This allow an extra fullsized PCIe slot to be placed next to the case. An external case... for a external GPU case. Inception. Great movie.
I find this concept pretty cool. This board can accommodate tree mini-PCIe cards like those, directly onto the board.
Sadly I haven't the time nor the reason to order and try every designs.
@lefuturdelavenir, This is cool as hell! Would this replacement board fit in the Razer Core X Chroma? It could possibly fix the "can't connect a USB hub to internal ports" issue if it uses different USB controllers to the ports on the back.
It would require some verification first. Electrical verification to check if the PCIe pinout is identical. And also mechanical verification. From the pictures I saw of the Core X Chroma, it’s not going to be easy to fit as the daughter board is sandwiched between the PSU and the graphics card. But it looks possible.
I noticed the daughter board is designed « upside down » on the chroma: the components are mounted on the other side of the PCB in comparison with the Core V2 and standards PCIe cards. By chance, USB3.0 board connectors are symmetrical and can be solder on the wrong side. If both end-connectors of the USB3.0 cable are mounted upside down, well... it should work 😀
I guess we should look for a proud owner of a Core X Chroma that is willing to give it a try!
Here are some pics of the mod. I took those while taking my Core v2 apart in order to put it back to it's original state. I'm willing to sell my macbook for a desktop computer and therefore I don't need eGPU anymore.
I'll publish the PCBs gerber files on Github when I have the chance. Hope it'll give someone ideas!