I already test all v5 firmware update. This is my experience:

TD-W8951_V5_140226 - not too much speed differences with default riger setting

TD-W8951_V5_140306 - boost the download and upload speed by more than 40x faster. But not for too long, download speed back to regular and leave upload speed still boost up to 40x faster.

TD-W8951ND_V5_141114 - cant access the internet whatever i do.

TD-W8951ND_V5_160113 - internet only can be access by cable with speed almost 50x faster on download and upload, but wireless is pretty much useless because wifi not detectable whatever i do.

So now im using TD-W8951_V5_140306 firmware. Its such a pain to watch the download still like before and upload now just about 10x faster.
I dont know where is my mistake, i follow all the suggested steps.
What i know clearly is im having a headache lol.