This is a project I've been working on to create a custom riser board for Lenovo Tiny5 series (M720q/M920q/M920x, etc) to support an additional two M.2 SSDs as well as a 10G Ethernet card. It builds on badger707's excellent work investigating PCIe bifurcation and adding a second M.2 slot to these systems.
Fully loaded with this riser, an M920x can support four M.2 2280 M-key SSDs, as well as an additional PCI card, a SATA boot SSD, and an M.2 2230 E-key module. It also provides a standard 12 volt fan header.
Block diagram:
According to the IQ3X0IL board schematics, the system +3V3 rail is rated for 9.74 amps, and is used for various onboard components as well. A typical M.2 SSD is specified for 2.5 to 3.0 amps so four of them at full load could exceed the power supply capacity. The riser board therefore uses a buck converter from the +12V rail to avoid overloading the system +3V3 supply.
In addition to the power supply and clock buffer, a custom-programmed GreenPAK is used to handle power sequencing and ancillary PCIe signals like PERST# and CLKREQ#.
As of 5/14/2024, I have a production batch of these and am now selling them, see issue #1.
Using this requires soldering two 0402 resistors on the motherboard to enable PCIe bifurcation.
There is also a mounting bracket to hold the additional M.2 drives in place. It replaces the WiFi antenna support at the front of the case.
This design is EXPERIMENTAL and provided WITHOUT WARRANTY. It has not been approved by Lenovo, the FCC, or really anybody. I am not responsible if it breaks your computer, deletes your data, burns down your house, or kicks your cat.