We have 2 B200 M3s in a new deployment running 2.0(3a). The B200s are configured with 64GB using 8GB DIMMs, using BANK 0 of each channel. We've deployed a BIOS policy specifying performance mode for LV DDR, and confirmed this setting took effect within the BIOS, yet the memory continues to run at 1333MHz. When looking at the server inventory, the DIMMs are reported as dual rank 8GB 1600MHz DIMMs. We've tried forcing the DIMMs to low-voltage mode and back to performance mode to no avail.
In other UCS environments, we've deployed these same blades with the same memory configuration and BIOS policy and had no issues getting the RAM to run full speed. We're not using any kind of power capping either.