Mine is DIY ah... Previously I bought additional 4GB ram (Corsair) but failed to boot. Finally checked and found that they are not in the same firmware version as those I bought in Day 1 thus not stable.
This time 漢科's 鍾生.. is very very ok wor.. good follow up. may be he is the supervisor in head office (actually just a "warehouse") He even helped to go office earlier at 8:30am twice time so that I can send and pick up my PC.