Trouble Adding Memory

[Hadders]

Jim Duda wrote:
> I'm running Fedora Core 5.
>
> I have a plain vanilla 2.8Ghz P4 Intel motherboard with 4 DIMM slots.  
> I currently have 1 DIMM of 512M DDR 3200 memory.  I purchased a second 
> DIMM of the same 3200 memory hoping to upgrade the memory.
>
> When I install the second DIMM, the BIOS properly recognizes it, 
> however, FC5 won't boot properly.  The boot time takes forever.  The 
> bootup is sitting in "Starting UDEV" for a very long time.
>
> I believe the new memory DIMM is okay, I can use either memory DIMM 
> properly, however, attempting to use both causes a problem.
>
> I'm stumped as to what could possibly be wrong.
>
> I don't use the stock FC5 kernel, but instead have compiled my own 
> 2.6.18-1 kernel.  I have the Memory Split option set to the default 
> 3G/1G user/kernel split.
>
> I don't know if this is the correct list to ask this question.  Does 
> anyone have any suggestions?
>
> Jim
>
Yeap, check the voltage settings and also check the CAS between the two 
DIMMs. This is Column Access latency, some are faster than others, that 
can throw the timings out too.

Finally, modern DIMMs are designed to be paired to run Dual Channel mode 
for faster front side bus speeds.  You've likely enabled dual channel 
mode, make sure that the DIMMs are where they're meant to be. I see 
PC3200 = DDR400, which means they should handle 800Mhz FSB, which is the 
max FSB speed of your proc.

H