2018 15" HP Spectre X360 (VegaMGL) [8th,4C,G] + RX Vega 64 @ 32Gbps-TB3 (Razer Core X) + Win10 [Kid]
2018 HP Spectre 15-ch000 x360 Convertible
HD Graphics 630
RX Vega M GL
Razer Core X
Sapphire Nitro+ Radeon RX Vega 64 8GB HBM2 Limited Edition
Monoprice Thunderbolt 3 (40 Gbps) USB-C Cable, 100W, 2.0m
Seasonic Prime Ultra Titanium 1000W
Noctua NF-F12 industrialPPC-3000 PWM
Since my GPU requires three 8-pin, I have to replace the PSU. Simply route all the cables through the opening for the original PSU's switch and cable and place the PSU on top of the enclosure.
I replaced the stock fan with a Noctua one. My GPU comes with two 4-pin fan connectors so I used them instead of the 3-pin one on Core X's board.
Drivers are tricky in my case. RX Vega M GL is officially supported by Intel branded Radeon drivers which hasn't updated since Jan 2019. Official AMD drivers setup utility does not recognize this GPU. The inf file has Vega M GL in it with some device id mismatch. Force install through device manager works fine and then you can manually install Radeon Settings. Since I have a Vega 64, I can take advantage of the setup utility to install Radeon Settings.
- Connect eGPU
- Uninstall all AMD drivers with DDU in safe mode.
- Run drivers setup utility
- Force install driver for Vega M GL by inf file in device manager
- This specific version of Spectre comes with a 150W charger while the CPU+GPU is limited at 65W TDP. Charging through USB-C power delivery appears to be around 60W. I cannot get the exact number since I don't have an USB-C voltage and current meter. PD charging should be enough in most cases except heavy load like gaming.
- I haven't take apart the laptop to repaste it yet since I would prefer to do that after warranty period. CPU idle temperature is about 55°C and any load that triggers CPU boost clock will increase the temperature to about 95°C instantly. Any GPU load will make the thermal constrain even worse and compete TDP headroom with CPU so eGPU is especially helpful in this case. Apparently due to design issue with this CPU+GPU package, the heat sink for Kaby Lake G doesn't apply enough pressure. Combine that with inadequate heat sink and OEM paste job, thermal throttling is unavoidable even with undervolt. Looking by pictures from https://www.reddit.com/r/spectrex360/comments/8ua3c3/spectre_x360_15_vega_repaste_photos/ , the PCH doesn't have any cooling at all which could be a problem for eGPU through TB3.
- Kaby Lake G is an interesting CPU in terms of its design. The CPU part of 8705G and above is exactly the same as 7920HQ. The GPU part is a mixed breed of Polaris with HBM controller from Vega. The flagship 8809G is unlocked for OC on CPU/iGPU/dGPU/HBM. The unadvertised perk for the other locked Kaby Lake G CPUs is an extra 600 MHz OC ability. Both ThrottleStop and XTU can be used to do this. You can see that my CPU is boosting at 4.7 GHz on single core during idle in the 3DMark benchmark. GPU side is locked from using WattMan but soft power play table can do everything you want like undervolt and OC.
- Another impact from the CPU design is PCIe hierarchy. Vega M GL is connected to CPU with EMIB which is x8 but HWiNFO shows that it's a x8 connection running on a x16 bus from CPU. TB3, Wi-Fi, card reader, and SSD are connected through the chipset. I'm not sure if the PCIe lanes from CPU can split into two x8 or not.
- The new Razer Core X Chroma should be possible to put larger PSU like mine inside. The old version has two problems: misaligned opening on the panel and limited size by the PCB. The new version revised the PCB so it can accommodates larger PSU. If there is enough space, it should be possible to leave the PSU cable inside the enclosure and route it through the opening. Power switch will be inaccessible or difficult to access but most likely you will not need to use the switch at all.
- I accidentally stripped two of the screws on the stock fan. Unfortunately I found https://egpu.io/forums/psu-cables/razer-core-x-120mm-case-fan-upgrade-strange-behavior-of-replacement-fans/ after the accident. Now my fan is mounted with only two screws but it is stable enough for 3000rpm.
- Fan behaviour is weird with my setup. The Noctua fan stays at lowest speed during normal use and doesn't ramp up even if the eGPU fan ramps up. It will operate at max speed in sleep mode since the eGPU is in sleep mode too which stops providing PWM signal. It will shutdown with the laptop so no issue here. I disabled sleep mode when connected to charger to get around the issue.
These Sapphire Nitro RX Vega 64 cards are massive! Have you considered removing the enclosure fan bracket as well as PSU bracket? There are mounting holes behind the front fascia to mount a 140mm fan. That way you can fit the Seasonic 1000W PSU inside the Core X.
I did try that but unfortunately the problem lies with the placement of 24pin and 3pin fan connectors on the Core X's PCB. No matter where you put the PSU it needs 86mm width but the part of the PCB with the connectors sticks out and cuts into the 86mm line.
What was your software installation process? Did you use AMD's drivers or the Intel drivers for the Vega M GL? I'm trying this with an Intel Nuc Hades Canyon (HVK with 8809G but same Vega M GL) and a Radeon VII in a Razer Core X and that's the only hang up.
Once you double click the exe from AMD, it will extract the files to C:\AMD\[driver version]. The inf file is inside \Packages\Drivers\Display\WT6A_INF. Browse this directory in device manager to force install it. There will be two entries of your GPU name because there are two inf files. Pick any one of them will work.