I have a Fujitsu-Siemens Scenic P300 i845GE with this 256 MB RAM :

Memory Module Properties:
      Module Name                                       Hyundai HYMD232 646A8J-J
      Serial Number                                     2D05422Ch 
      Manufacture Date                                  Week 21 / 2003
      Module Size                                       256 MB (1 rank, 4 banks)
      Module Type                                       Unbuffered
      Memory Type                                       DDR SDRAM
      Memory Speed                                      PC2700 (166 MHz)
      Module Width                                      64 bit
      Module Voltage                                    SSTL 2.5
      Error Detection Method                            None
      Refresh Rate                                      Reduced (7.8 us), Self-Refresh

    Memory Timings:
      @ 166 MHz                                         2.5-3-3-7  (CL-RCD-RP-RAS)
      @ 133 MHz                                         2.0-3-3-6  (CL-RCD-RP-RAS)

    Memory Module Features:
      Early RAS# Precharge                              Not Supported
      Auto-Precharge                                    Not Supported
      Precharge All                                     Not Supported
      Write1/Read Burst                                 Not Supported
      Buffered Address/Control Inputs                   Not Supported
      Registered Address/Control Inputs                 Not Supported
      On-Card PLL (Clock)                               Not Supported
      Buffered DQMB Inputs                              Not Supported
      Registered DQMB Inputs                            Not Supported
      Differential Clock Input                          Supported
      Redundant Row Address                             Not Supported

    Memory Module Manufacturer:
      Company Name                                      Hynix Semiconductor Inc.
      Product Information                               [url]http://www.hynix.com/eng/02_products/01_dram/index.jsp[/url]

I wanted to upgrade (I bought a 512MB DDR PC3200 400MHz RAM)
Well, I have 2 slots, the 256 was in the upper one, I installed the 512 in the lower --> PC does not work (beeps)
So, I tried the following :
512 in upper, nothing in lower --> beeps
256 in lower, nothing in upper --> Beeps
256 in upper, nothing in lower --> works

I thought my 512 RAM was defective but it worked OK on my other PC (which has PC2100 256x2 RAM) :rolleyes:
I thought the lower slot was defective, but putting the 512 in the upper and nothing in the lower did not work !! :rolleyes:

And if my 512MB is not detected, why doesn't my PC start with 256MB RAM???:twisted:
I am getting confused, help me please :eek:

Sorry, I tried again and it worked with the 256MB RAM in the lower slot.
Thus, the RAM I bought seems to be incompatible !!! (it's an NCP DDR PC3200 2.5V one)
It should have worked, but it did not. Does anyone know why?