4600 Memory upgrade

i have x2 PC3200 256mb sticks in my 46000 and would like to add 1G. I have 2 questions

1. will i be able to put only one extra stick in or do i have fill both of the 2 extra slots?

2. im looking at PC3200 DDR400 184 DIMM ram but the run at 6.4GBps...will it be compatable with my 4600?


i read this:
# Dimension_4600:
Chipset: Intel 865PE.
Has 4 memory sockets.
Each socket has a maximum capacity of 1GB.
Minimum system RAM is 128 MB.
Maximum system RAM is 4GB.
Uses DDR-SDRAM PC2100, PC2700, PC3200.
Uses NON-ECC memory.
System documentation located here.






# The Front Side Bus speed of the processor directly affects the
speed of the memory. See the chart below.
Memory Speed Configurations
ProcessorFSB-----DIMM speed-----Actual Memory Speed
400MHz...........266MHz.........266MHz
400MHz...........333MHz.........266MHz
400MHz...........400MHz.........266MHz
533MHz...........266MHz.........266MHz
533MHz...........333MHz.........333MHz
533MHz...........400MHz.........333MHz
800MHz...........400MHz.........400MHz
800MHz...........333MHz.........320MHz
800MHz...........266MHz.........266MHz
*PC1600 200Mhz memory will not work in this system.

Data transfer rates: DDR SDRAM
Name------Clock Speed------Single Channel------Dual Channel
PC1600....200MHz...........Will not Work.............Will not Work.
PC2100....266MHz...........2.1GBps.............4.2GBps
PC2700....333MHz...........2.7GBps.............5.4GBps
PC3200....400MHz...........3.2GBps.............6.4GBps

it says right here at the bottom that PC300 400mhz 6.4 WONT WORK! then what should i get?


im stuck! help.