My Dell Dimension 4700 is not recognizing newly added memory

[eandres]

My Dell Dimension 4700 is not recognizing 2-1G newly added memory (DDR2-6400). I did keep an existing 1G memory card I used to upgrade (back in 2007) the original 512MB that came with the machine. I am not sure why the computer is not recognizing the additional memory. Do I need to replace the existing member as well when I add the new memory?

 

[poma5]

My Dell Dimension 4700 is not recognizing 2-1G newly added memory (DDR2-6400). I did keep an existing 1G memory card I used to upgrade (back in 2007) the original 512MB that came with the machine. I am not sure why the computer is not recognizing the additional memory. Do I need to replace the existing member as well when I add the new memory?

Take out all of the memory and then put the two new 1Gig memory sticks in slots 1 and slot 3. Slot 1 is closest to the CPU or the farthest slot into the middle of the mother board. You should have two white slots and two black slots. Put the new ones into the two white memory slots. Try booting the computer then. It should boot fine.
Your memory is what is call double data rate V.2 memory so they should be installed in pairs for maximum performance. If you really want to add the rest back I would buy on 2 more 1Gig sticks and install them in the black slots. The other option is to find another 1 gig memory stick that matches your old memory stick exactly like pc2 1gig at 400 or 533mhz and then install them. Toss the 512meg or save it for a really desperate friend.
For maximum performance these need to be installed in matched pairs as far as memory size and speed.

This is an older machine but if you can get into your bios you can make sure that your CPU is set for hyperthyreading which is not always set by default. Believe it or not that helps quite a bit as it allows your one CPU processor to process more than one thread at a time. It is like having a dual processor and will speed things up a bit.

Good Luck!