Mixing RAM speeds - ddr266 with ddr400, etc

[Kaido]

How does RAM do with mixing speeds? Like, if I have ddr266 and ddr400 is on sale, the ddr400 will run at ddr266 speeds when I install it, right? I have some friends who are looking to upgrade, plus my main comp - a Dell 4600 - has 2x256mb ddr333, and there are some good deals on 256mb and 512mb of ddr400 floating around. I'd like to keep what I have and add more since I have a total of 4 banks.

Will it cause any stability problems by mixing? Heat issues? Will it neuralize me unless I wear Ray-Bans?

 

[JBT]

mixing is fine.