I have yamaha HS8's, I just got a new computer and the onboard audio isn't near as good as it was on my previous motherboard.

[silverblue23]

Audio DAC for powered studio monitors

 

[hang-the-9]

Get an add-on audio card. This is a good cheaper model and has a good headphone jack so you can use higher end headphones also. https://www.newegg.com/Product/Product.aspx?Item=N82E16829102062

 

[americanaudiophile]

An outboard USB DAC would be better. Removes the analog circuitry from the PC completely and isolates the DAC from the mobo power supply. Doesn't have to be expensive.
http://www.schiit.com/products
If you record an audio interface with monitor out would work too I think.