32 will definitely work. 250 might be questionable in terms of volume/quality.
my suggestion would be to get a good sound card at the same time, then you can make sure that 250ohm is supported, and it sounds a lot better than on-board sound.
This will also help you get the most out of the DT990.
If you also want to use the headphones with a smartphone or something, only the 32 will really work.