Choppy asterisk on NSLU2 unslung 6.8

i am having choppy sound issues with the NSLU2 unslung asterisk.
I am wondering if it is due to memory or codec (ulaw/gsm/slin only)issues. Internal calls seem to be great, but external calls out seem choppy on both ends , however leaving voicemail tomy cell voicemail (not asterisk voicemail) seems to sound fine, although the cell voicemail system itself was difficult to hear due to choppiness. I only have one module added from the sample configuration (privacy manager).

the exact same .conf files work, no issues, under a vanilla asterisk box.

I am wondering if it is the codecs. some memory seems to be free and i have loaded only the barest packages (openssh, bash, nano) to get the unslung asterisk up.

any help would be great.