what i mean by lag / pause:
1. screen rotation, portrait to landscape and vice versa
2. activating camera
3. opening apps, especially heavy games
4. searching songs in playlist (maybe bcoz of my 700+ titles inside)
5. received sms, then when press Open, phone will paused for 2-3 secs before msg is shown
6. deleting pics in photo gallery, after that everything will stop awhile
7. ppl call in, and the phone in 'portrait mode', then u take ur phone out from pocket, and the phone will go into 'landscape mode' bcoz accidentally rotated the phone, and while that happened, the ringtone will lag a second (very very embarassing for me when this happen

)
for no.1 and no.7, i already 'solved' the problem by turning off the auto rotate feature.
congrats if ur x6 dont have the above problems
my C drive is 197mb free out off 2xx mb
D got 7gb free as i hardly use D
memory card 4gb, but still 500mb free