Your AKG K550s can be driving from just about any headphone jack on the planet.
(it's the kind of powering it's get is the question)
You can plug your headphones straight into the gaming computer and see if you like the sound.
What make and model is the motherboard?
Is there an add-on sound card?
If you decided to add on an external headphone amplifier, what would your budget be?
The O2 (Objective 2) portable headphone amplifier (new $155) would be a good investment as chances are it would work with any headphone (16-Ohm to 600-Ohm) you buy in the future.
And it come with a very low impedance, like 0.5-Ohm, and it works fine as a desktop head amp.
Something as cheap as the Fiio E6 ($27.50) headphone amplifier, might make a difference, as it's also low impedance.