I have four new (to me) sticks of Kingston 1Gb 400Mhz DDR2. Three of them boot fine individually in slots 1 or 3, but not in slots 2 or 4. The fourth does not boot in any slot.
The three working ones do not boot in any combinations of slots.
1234 (channel numbers) 1000 0010
1234 (channel numbers) 0100 0001 1100 0011 1010 1111 (naturally, as one stick seems duff)
However, with my old memory, a single 1Gb 667Mhz DIMM, the computer will boot no matter which channel I put the DIMM in. Any combinations of new and old also fail to boot.
My question is similar to Can't get memory sticks to work together, except that even combinations of known-good DIMMs do not work, and similar to Memory works fine separately, but not together, except that I can't boot the faulty stick to change the BIOS settings for it.