DDR400 sync problem to lower speed?

I have three identical Compaq EVO DC510 systems. I am trying to max out the RAM at 2GB: 2X1GB.
The info from compaq claims that either DDR333 or DDR266 should work, but I bought DDR400-rated parts because the mftr claimed "backward compatibility". obviously that is not universally true because the system fails POST no matter how I try to use these parts. Voltage and everything else spec-wise checks out per the book.

So now, I'm stuck. DDR266 mem seems to be fairly rare in 1GB sticks.

Anyone have some advice for me.... i'm sort of frozen in tracks

 

are you sure your mobo even supports that much RAM?

yea ur right, the RAM should and will reduce its speed to run at the max speed of that mobo. Have you tried just running one stick at a time to see if one is bad?

 

Do you mean D510? If so, Crucial says you can use 2 x 1GB either DDR400 or DDR333. They don't seem to know about there being a DC510.

http://www.crucial.com/store/listpa...el=Evo+D510+Series+All+Form+Factors&submit=Go

 

yeah, i know what the Crucial monkey SAYS, but Cpq's info is diff.
STILL, I thought sophisticated DDR like this could sync SLOWER, just not faster.

from the EVO DC510 convertible minitower [what i have] H-Ref: [hey, can anyone explain what a "x4" SDRAM is?]

The memory sockets on the system board can be populated with
industry-standard DIMMs. These memory module slots are populated
with at least one preinstalled memory module. To achieve the
maximum memory support, you may be required to replace the
preinstalled DIMM with a higher capacity DIMM.
DDR-SDRAM DIMMs
For proper system operation, if your system supports DDR-SDRAM
DIMMs, the DIMMs must be industry-standard 184-pin, unbuffered
PC 1600 200 Mhz- or PC2100 266 Mhz-compliant, 2.5 volt
DDR-SDRAM DIMMs. The DDR-SDRAM DIMMs must support
CAS latency 2 or 2.5 (CL = 2 or CL = 2.5). They must also contain
the mandatory JEDEC SPD information. DIMMs constructed with x4
SDRAM are not supported; the system will not start using
unsupported DIMMs.
✎ The Intel 845-G chipset does not support ECC memory.