I need some help here regarding a new RAM tat i get to fit in my DFI Nforce 4 Ultra D.

My ram is exactly the same as the pic in the first post, the only different it is APACER brand.

Ram details : APACER 1GB PC3200 CL3 double sided (with Samsung K4H510838C chip on it)

My present computer already got Corsair 2x512MB PC3200 CL2.5 RAM.
But when i plug in this single stick on my board it seems cant boot.
I already tried put this APACER ram on board stand alone on every slot ( means i took all both of my Corsair ram) but it still cant boot up.
And i tried it too put it in any of the ram slot while both of my corsair ram is already plug in too.

3rd test, i tried it with slot 1 512MB corsair n 3rd slot with 1GB apacer or even do it opposite way. but still cant boot up

Both way also cant boot up, the question is
is it bcos of dual channel matter? As i dont hv another 1 GB ram to test it.
or is it bcos of APACER 1GB this ram is not compatible with DFI Nforce 4 Ultra D motherboard?

Hope some sifu out there can help me. Thank you