Posted 08/07/2008 at 08:38:55pm

Don't take my word on it just look at the performance delta on AMD processors when you have two mismatched DIMM sizes on a Dual DRAM controller product. Answer memory bandwidth drops because.....You guessed it imbalanced load cause this config to behave like a single DRAM channel.

Posted 08/07/2008 at 08:27:08pm

If he new anything about DRAM controllers or why dual channel is better than single channel he would never have made the statement that 2M, 1M, 1M would opperate at full speed. This configuration will load one controller more than the other two and will reduce the performance not increase it.

As for 3 DIMMs not helping much over 2 DIMMs this is most likey also not going to change with a BIOS update. Load balancing between any non power of 2 address space is a tricky problem to solve in hardware. It can be done but it requires a lot of logic and it is never extreamly effective.  The best load balancing is done when you can evenly balance the address space between all channels such that linear accesses alternate between channels.  How do you make that work when you have an odd number of channels??