Very slow performance after memory upgrade

Problem:

When upgrading the system to 6 modules per CPU bank, memory performance is extremely poor.

Affected Platforms:

Solution:

This problem is fixed by updating the BIOS to the latest version:

ftp://ftp.aslab.com/pub/bios/supermicro/x8dt3.zip

  1. Extract the files to a DOS bootable USB memory stick
  2. Boot to a DOS prompt and type AMI.BAT filename.rom.
  3. Do not interrupt the process until the flashing is complete.
  4. If the computer pauses, please wait until it starts to program.
  5. The computer will re-boot on completion.

After reboot, press F2 to enter the BIOS setup. Then set the following BIOS parameters: 

Exit->Load Optimal Defaults
Main->Set Date and Time
     
Advanced
  BOOT Features
     Quick Boot [Disabled]
     Quiet Boot [Disabled]

  Processor & Clock Options
     Intel Virtualization Tech [Enabled]
     Simultaneous Multi-Threading [Enabled]

  Advanced Chipset Control
    CPU Bridge Configuration 
       QPI Frequency [Auto]
       Memory Frequency [Auto]

    North Bridge->NUMA Support [Enable]
    South Bridge->Legacy USB Support [Enabled]

  IDE/SATA Configuration
     Configure SATA#1  [AHCI]
     HotPlug [Enabled]

  PCI/PnP Configuration
    LAN1 PXE->[Enabled]
    LAN2,3,4 PXE->[Disabled]
   
  SuperIO Configuration->Floppy A [Enabled or Disabled]

  System Health Monitor
     Fan Speed Control Modes [4-pin Server]  
 
  ACPI Configuration
    ACPI Version Features [ACPI v2.0]
    High Performance Event Timer [Enabled]