Thank you all for solutions you suggested.
I know assigning a fixed IP for my One X on my router would solve the problem.
The problem is, I also connect to my work's router.
And dropouts/slowdowns still exist.
My home router is Cisco LinkSys WAG120N
Anyways, HTC are aware of this bug.
Hopefully a FOTA will release to solve miscellaneous bugs including
- WiFi BUg
- Battery life (misplaced apk file in stock-rom)
I know people starts having FOTA with software number: 1.27 to replace the 1.26 version.
Hope it rolls soon.
Thank you all again.