Yes evilhippie please link the information that confirms that the SGP 5.0 and 4.0 both use the Wolfson WM8994 DAC. I have not seen anything confirming this yet, I would love to see if anyone has torn a 5.0 apart or has full manufacturer specs.
Here is the last info I saw regarding the DACs in the Samsung Galaxy players: http://www.anythingbutipod.com/forum/showthread.php?t=64069 - notice the question mark next to the YP-G70 (SGP 5.0)
Whatever DAC the 5.0 has uses very little power and virtually zero CPU resources with the stock music player software. I think that their may be another audio processor chip that offloads much of the CPU load. In comparison, I see that Neutron uses 19-40%+ of the CPU resources while it is running and roughly 4-5% more power. I attribute this to the DSP processes that Neutron uses along with a tiny bit of sloppy coding. This extra use of resources may also be because Neutron, and I suspect PowerAmp, are designed to be universal full featured Android players versus something that is optimized to only one device like to stock software may be.
Right now I am A-B testing PowerAmp and Neutron. Neutron sounded good in my car today, a lot better (louder with less distortion) than the stock player software. Tomorrow PowerAmp gets a through test in the car. I plan to write a review of my experience with each APP along with my decision making process for selecting one over the other.