Pros: Easy to install. Works wonderfully in my Dell E521 which originally had a single core Athlon 3200+. A low price upgrade that runs faster and cooler.

Cons: None so far...

Overall Review: Added two 1Gb DDR2 800Mhz memory sticks to spice it up a bit more. Dell originally shipped with one stick of 533Mhz. So it wasn not taking advantage of the DOUBLE data rate memory capability.