DDR Server Memory Issues

[GWXerxes]

I have an Asus K8N-DRE Server motherboard that I have been trying to get to work for a few days now and finally decided to post in here. Its rather old and uses DDR ECC Registered Buffered memory. I bought 2GB (8x256) of PC2100 266Mhz Crucial memory for it and much to my surprise the system only recognized half of the memory. I called Asus tech support and after scolding me for using a 7 year old motherboard they told me that the board was built to run PC3200 and then hung up on me. After playing around in the BOIS I set the Memclock mode to Limit and the Memclock value to 266 MHz. When I rebooted all 2GB of ram was recognized. But when I rebooted again only 1GB with a Memory R/W Fail. I checked the settings and rebooted aend it was back to 2GB. To make a long story short this went on for quite some time and the system keeps alternating with each cold boot from 1 to 2 GB of memory detected. My question to the good people of overclockers.com is: What could possibly cause this and if we do fix the alternating then is it still a good idea to use the lower memclock when the board was designed for higher?

System
Motherboard: Asus K8N-DRE
RAM: 2GB 8X256 Crucial DDR ECC Registered Bufferd
Processors: 2x AMD Opteron 2.0 Ghz

Northbridge BOIS Config
Memclock Mode: Limit
Memclock Value: 266 MHz
User Config Mode: Manual
CMD-ADDR Timing Mode: 1T
Burst Length: 4 Beats
HardWare Memory Hole: Disabled
DRAM ECC Enable: Enabled
ECC Chip Kill: Disabled
NUMA Function: Enabled
IOMMU Mode: Disabled

--EDIT--
Using Memtest86 ALL of the memory failed the test. I don't see how that's possible though since the computer was booting. Also any Linux Live CD I use fails to boot

 

[kraven]

Systems with bad memory can still boot but then fail when the bad sections of memory get allocated. Think of a cup with a hole towards the top. Everything's fine until the water gets to the hole.

Does the RAM have a lifetime warranty? Try an RMA and see if that helps.