Abit AN8 ULTRA and 1.5Gigs problem, HELP!

[Kalero]

Ok here is the problem.
I have 2*512 DDR PC3200 Corsair 3200C2 PRO in dual channel.
I took another 512 DDR PC3200 (no-name) from my office...
when i put all 3 * 512DDR=1.5Gigs it won't boot
i tried all combinations in all slots.Sometimes it boots ---> black screen and beep.
sometimes it boots and it hangs at boot screen...
when i boot only with the 512 non name, it works.
1x 512 Corsair + 1x 512 No-Name, it works
All 3 dimm's together and it doesn't work...
wtf is wrong?
thanks

PS: i run at default speeds and spd.

[nn_step]

no Amd memory controller likes mismatched pairs let alone a solid set and a half set.. It is not one of the supported combinations.. get another stick of ram or remove that no name, now.

[Kalero]

i already fixed it.
i changed from 1T to 2T command.
problem solved.
thanks