computer audio question

Different DACs can sound very different. How different will depend on what DAC you are using and what replacement you are getting.

Different software players can sound different too and in some cases, they sound more different from one another than different DACs do.

Changing a DAC is akin to changing a cartridge. As Sidssp implied, do not discount the transport aspects too. There has been great strides made in that arena through the use of computers as the digital transport mechanism including the player software and file types.

There are processors with freon cooling instead of fan which are much more quiet than fan cooled ones. That could be the tweak becides DAC, but as previously mentioned DAC makes the largest difference.