AMD RD790, RD780 & RX780 BIOS to feature AutoXpress

Posted on Monday, Sep 24 2007 @ 15:35 CEST by Thomas De Maesschalck
Our colleagues from Chile Hardware discovered motherboards based on the AMD RD790, RD780 and RX780 will have a special BIOS option called AutoXpress.

Feature Options: ON (default) / OFF / Custom
Upon selecting CUSTOM option - 3 options that have no submenus appear (the details listed below are hidden). These options only have two modes ON or OFF. Selecting ON selects ALL functions in that mode.
  • CPU (ON default /OFF)
  • XpressRoute (ON default/OFF)
  • MemBoost (ON default/OFF)
  • CPU (ON / OFF)
  • Function 1: To Maximize CPU performance
  • Detail: Change CPU ClkDivisor to "Divide-by-1" mode
  • Limitation: For Phenom (K10) CPU only
  • XpressRoute (ON / OFF)
  • Function 1: To accelerate transfers of data to and from graphics
  • Detail: Increase PCIE clock for Graphic cards with certain device ids. Internal qualification has been done on R600 and R580+ cards and has shown stability at 150Mhz-160Mhz on the PCIE bus (Gen1). Corner lot testing has shown that 125Mhz should be the recommended default to cover worst case scenarios.
  • Limitation: For RD780 and RD790 only.

  • Function 2: To accelerate transfers of data b/w graphics (most notably in SW CrossFire)
  • Detail: Enable BIOS setting to allow P2P transfers
  • Limitation: For RD780 and RD790 only

  • Function 3: To maximize transfer bandwidth of graphics data with a HT1 CPU
  • Detail: Enable BIOS setting to double pump graphics data across HyperTransport
  • Limitation: For RD780 and RD790 only. For HT1 CPUs only (disable for HT3 CPUs)
  • MemBoost (ON / OFF)
  • Function 1: To accelerate memory bandwidth performance with DDR2-800 or higher DIMMs with K8 CPUs
  • Detail: Alter memory timings for DDR2-800 or higher DIMMs
  • Limitation: For RD780 and RD790 only. For DDR2-800 or higher DIMMS. For K8 CPUs only.

    Fine tuning adjustments: Trc, reduce by 2
    Twr, reduce by 2
    Trrd, reduce by 1
    Tref, 7.8us instead of 3.9us
    Twtr, reduce by 1
    BankSwizzleMode, Enable
    Queue Bypass Max. increase to 7

  • Function 2: Disable DRAM PowerDown mode
  • Detail: Change register to 0
  • Limitation: For RD780 and RD790 only.

  • Function 3: Read Enthusiast DIMMs with multiple SPDs
  • Detail: Read Performance SPD that gives maximum performance
  • Limitation: For RD790 only.

    Information on the performance gains will follow soon.


  • About the Author

    Thomas De Maesschalck

    Thomas has been messing with computer since early childhood and firmly believes the Internet is the best thing since sliced bread. Enjoys playing with new tech, is fascinated by science, and passionate about financial markets. When not behind a computer, he can be found with running shoes on or lifting heavy weights in the weight room.



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