Dell Dimension C521 Memory upgrade - can I use 2 x 1 GB DDR3 10600U 1333MHz 240 Pin Non ECC Un-buffered to replace 2 x 512 MHz DDR2 SDRAM 667 MHz?
Dell Dimension C521 supports only DDR2 memory as mentioned in the above post. It takes upto 4GB of memory. It has 4 slots and the memory is evenly allocated to the slots i.e, max each slot take is 1GB.
4GB of memory is enough to run most of the applications and if you are not using your system as a workstation or if you are not using high memory intensive applications like CAD, Video rendering then this system would be more than enough for another year or so. If you are considering a system upgrade then wait until DDR4 and its compatible motherboards are released (IMO, maybe within next year). Cheers, mate!!