Memory doesn't fit in the slot

Will this work:

Kingston ValueRAM 2GB 240-Pin DDR2 FB-DIMM ECC Fully Buffered DDR2 667 (PC2 5300) Server Memory Model KVR667D2D8F5/2G

From what I've read I will have to upgrade the bios to A07

CADPARTSUSA,

The dimms are not supported in the 1800. They are not correct in size, the 1800 only supports up to 2gb dimms.

 The specs for the correct dimms would be 2gb DDR-2 400MHZ PC2-3200.

4GB DIMM's are not supported, but that isn't why it doesn't "fit".

The 1800 requires Registered ECC memory and cannot take Fully-Buffered memory.  Fully-Buffered and Registered memory are different - and generally incompatible - so they are keyed differently.  You will need to find 2GB Registered ECC DIMM's (DDR2 400MHz (PC2-3200) speeds are officially supported, although speeds up to 667MHz may work with the latest BIOS).

No, it won't work, because it is Fully-Buffered memory.  The memory you have doesn't fit because it is Fully-Buffered, NOT because it is 4GB.  Fully-Buffered and Registered memory have the key-slot in a different location to prevent you from using one in a system that supports the other, as they are incompatible.

KVR400D2S4R3/2G (single-rank)

KVR400D2D8R3/2G (dual-rank)

Thank you very much. I think I understand now. I checked and the Dual ranked need to be in the first 4 slots. It's been a tuff road since our IT guy quit. As you can tell I'm not very good at IT the info you've provided is very much appreciated. I'll order up the new memory and give it another try.

No problem ... good luck.

Refer to the manual for dual- vs. single-ranked DIMM's and the allowable configurations.