CAS lantency should be higher with DDR3, just as DDR2 has a higher CAS latency than DDR. But the slower CAS latency is made up for by having a higher overall speed. Bandwidth is also increased with DDR3. From the last I read, DDR3 should be close to DDR2 pricing in 6-9 months. Further developement should also bring the CAS latency down with DDR3. Right now, unless a person has lots of money, and some people do, then its better to build using DDR2. Even Intel has recognized this by designing a X48 mobo that will use DDR2.