Adapter cards for discrete graphics card slots

In one example, an adapter card may include a circuit board having a male interface to be inserted into a discrete graphics card slot and a peripheral component interconnect express (PCIe) slot to communicatively couple a PCIe device. Further, the adapter card may include a voltage converter circuit disposed on the circuit board to convert a first voltage associated with the discrete graphics card slot to a second voltage corresponding to the PCIe device and a level shifter circuit disposed on the circuit board to modify a signal level in the discrete graphics card slot to a signal level in the PCIe device.