System Specs

Lenovo Y700-17ISK (2015, 17")

• CPU: Intel Core i5-6300HQ
• iGPU: Intel 530
• dGPU: GTX 960M
• OS: Windows 10 1607 (RS1)

eGPU Hardware

• ADT R43SG-TU (25 cm)
• EVGA GTX 970 SSC ACX 2.0+ (Part # 04G-P4-3975-KR)
• PSU: Dell DA-2 D220P-01 (18A)

Installation

1. The inside of the laptop, with a schematic overlay of the attempted setup:

Note that it says "Connector Location" as I was initially hoping to place a connector there (see comments below).

2. Optional prerequisite: enable full DMI link speed either (1) from the Advanced menu of a modified BIOS or (2) by editing UEFI variables with H2OUVE or similar tool.

3. Cut a hole in the bottom cover (the so-called "D" panel) to put the cable through.

Not the most beautiful hole you might have seen but it gets the job done.

4. Remove existing nVidia driver with DDU in Safe Mode. Otherwise, expect error code 31 in Device Manager: "The driver trying to start is not the same as the driver for the POSTed display adapter."

5. If you already got the -TU version, skip this step. Otherwise (if you got the regular version), note that the -TU version of R43SG is actually the same product as the regular version: the cable can be turned backwards after removing the tape that holds it, however this can be done only once (try again and it'll break).

6. Connect the adapter to the M.2 port.

7. Put the bottom case back on:

8. Place the external GPU card in the slot, connect the power, and boot the system.

I've just got this card second-hand, and have yet to remove the heatsink, reapply thermal paste and, yeah, also get rid of the stickers that were supposed to be gone before first use (years ago!).

9. Install nVidia drivers.

10. Optional: disable Optimus dGPU in Windows Device Manager, and then in the BIOS after reboot.

Benchmarks

Interface Speed

CUDA-Z

AIDA64 GPGPU

Comments

I first attempted the setup with R44SF (M.2 extension cable) as well to have a separate connector, which would allow me to disconnect the adapter more easily when not in use: it worked, however the performance was not acceptable (data loss during transfers, manifesting itself with textures not loading on time or at all). According to ADT (the adapter manufacturer), for stable performance there cannot be any connectors besides the onboard M.2, and the total cable length should not exceed 60 cm. They told me this in advance, I tried it anyway, and can now confirm that they know their stuff.

For a rough performance assessment, GTA V at 1080p with the onboard GTX 960M dGPU on Very High detail and no MSAA is at ~ 40-45 fps at most, with frequent drops to ~ 30-35 fps and below. Even on lower settings, it is difficult to go above 60 fps. On the other hand, the GTX 970 I got does Ultra with MSAA at ~ 70 fps average, and not < 50 fps at any time, and with MSAA off the numbers can reach 120 fps and more. These are based on just a quick preliminary test but it is obviously a different experience altogether compared to the GTX 960M.

The caveat is the need to give up the ability to use the M.2 slot for an SSD, which also means no NVMe. I was originally using an M.2 SSD along with a 1TB HDD. I used this as an opportunity to ditch the HDD altogether and upgraded to a 1TB (SATA3) SSD now that they're no longer expensive.

Comments welcome.