Ohm is the electric impedance (similar to resistance, R in this case). The raw electric power is calculated as "P=(V^2)/R" (not exactly, but works for this subject). As you can see, to calculate the power you have square volts divided by Ohms, therefore, higher the ohms, lower the power you will get. This is fixed by increasing the voltage a bit. As you can see, as your headphnes have double the ohms, you would need about 1.42 times the voltage. The voltage is, basically, the volume you choose.
Therefore, your motherboard will handle it with no problem, as the highest volume will still be very high.
You will just need to increase the volume a bit more than other headphones.