the 1150 chip is newer but is there a noticeable difference and is it worth changing the board?
Currently using ALC898 with AKG K99 headphones`
Not really...
If you are getting a new board, ALC 1150 could be a selling point. But changing the motherboard for this alone is pointless IMHO...
I am using it on my Asrock mobo... But... Hm, may be this is why my 10yo surround sounds so good...
But really now, don't...
its basicly just a codec.
How the quality of the audio is, highly depends on the parts they have used for the onboard audio cirquitry.
like which audio caps, which opt amp´s, quality of the ports they´ve used etc, not only on the codec it self.
I didn't notice a difference going from the Gigabyte 990Fx Ud3 Rev 4 which had the ALC898, to the AsRock Z97 extreme 6, which has the ALC1150. In my opinion its just a bigger, prettier number. If you had Senheiser HD800's maybe you could hear a slight difference. But that doesn't really matter if the audio circuitry around the chip is bad. That bit will make a difference in the sound signature.
The main diffrence between alc898 and alc1150 is that alc898 has upto 110db snr,
and the alc1150 has upto 115db snr