5x86.TXT  (Last Update December 5, 1995)


    This Frequently Asked Questions (FAQ) document is intended to
    assist with common customer questions on the AMD Am5x86-133
    32-bit CPU.

                      /**************************\
                      ** Am5x86-133 INFORMATION **
                      \**************************/

1.  Where can I get an electronic copy of this information?

    If desired, you can download a copy of this message from our BBS at
    408-749-4659  (5x86.txt in PCD conference 6).  There is additional
    information located on the AMD World Wide WEB at http://www.amd.com.

2.  Exactly what is the Am5x86-133 and what is the ordering part number?

    The Am5x86-133 is the latest 32-bit CPU available from Advanced Micro
    Devices.  This is an SL Enhanced CPU with a 16KB internal cache that
    supports write back and write through cache policies.  The pin-out of
    the Am5x86-133 is the same as the AMD Am486DX4 Enhanced (SV8B family)
    of CPUs.

    The exact ordering part numbers for the Am5x86-133 are listed below:

       AMD-X5-133ADW (168-pin PGA package, 3.45 volt, 55C case temp.)
       AMD-X5-133ADY (168-pin PGA package, 3.45 volt, 75C case temp.)

3.  I am having problems with my motherboard jumper settings.  Can AMD
    help to determine the best settings?

    We cannot answer motherboard specific questions, such as how to set
    jumpers or configure your CMOS setup.  You need to contact the
    motherboard manufacturer or consult your motherboard manual.  386
    motherboards do not support 486 CPUs and will require a new motherboard.

4.  Where can I find out whose motherboards support the Am5x86-133?

    For a listing of motherboard manufacturers, call our FaxBack or
    Literature Dept. at 800-222-9323 and get PID #19722.  Listings of
    motherboards compatible with the Am5x86-133 will be included in this
    document and will also be placed on the World Wide Web in the
    microprocessor section on the 3 volt Motherboard Listing page as the
    various motherboards are tested.

    There should be a number of compatible motherboards listed by the end
    of November or beginning of December.  Until that time you will need to
    contact your motherboard vendor about compatibility with the Am5x86-133.

5.  How can I tell if my motherboard supports the Am5x86-133?

    If your motherboard supports the AMD Enhanced line of 486 CPUs (the SV8B
    family) it will PHYSICALLY support our Am5x86-133.  The BIOS may have
    to be upgraded to run the Am5x86-133 in clock x4 mode since the CPU ID
    changes in this mode.

    However the BIOS on motherboards that properly support our Enhanced CPUs
    should be fully compatible with the Am5x86-133 running in clock x3 mode
    since the CPU ID is the same as the Enhanced 486 CPUs.  In this case the
    Am5x86-133 could be run as a DX4-100 or DX4-120 and get the benefit of
    the 16KB internal write back cache even if the BIOS will not support the
    device in clock x4 mode.

6.  What is the external bus speed for the Am5x86-133?

    The external bus speed is 33MHz. The Am5x86-133 CPU multiplies the input
    clock by 4!

    The CLKMUL pin on the older 486 Enhanced CPUs was high for x3 mode and
    low for x2 operation.  On the Am5x86-133 it is still high for x3 mode
    and should be jumpered low for the x4 mode of operation.

7.  After I installed the AMD CPU I seem to have some problems.  Do you have
    any suggestions?

    If you are having problems running HIMEM.SYS or DOS4GW.EXE check your
    motherboard CPU voltage and type settings.  Running a 3.45 volt CPU at
    the wrong voltage or setting up the motherboard CPU configuration
    jumpers incorrectly can cause these types of problems to occur.

8.  My CPU seems to run fine but the BIOS reports a different type.  Why?

    If your BIOS reports your Am5x86-133 as a different type of CPU, you
    may have a BIOS error or jumpers on the motherboard may not be set
    correctly.  To update an old BIOS you will need to get an update from
    the motherboard or BIOS vendor.

9.  Does AMD have warranty coverage for my CPU?

    If you have a damaged processor, it MUST be returned to the vendor from
    whom you purchased it.  We cannot help you here in technical support.
    AMD does not warranty parts to the end user.  The warranty coverage for
    your part is provided by the vendor you purchased it from.    

10. My system seems to run for a while and then fails.  Any ideas?

    If the board runs properly for some period of time and then seems to
    fail you may have a thermal problem.  The Am5x86-133 requires a heat
    sink and fan.  You will need to apply a thin layer of heat sink paste
    to assure proper heat transfer from the CPU to the heat sink.

    If you have intermittent problems check that the ISA bus clock is near
    8MHz.  The divider is in the Advanced CMOS setup.  For bus speeds of
    33MHz select clock/4 and for bus speeds of 40MHz select clock/5.

    Some green motherboards may try to slow down the processor.  It may be
    necessary to disable power management on Green PC motherboards to
    eliminate intermittent problems if the motherboard does not properly
    support the SL Enhanced power management features.  The Am5x86-133
    CPU does support the industry standard 2-pin SMM mode.

11. I seem to have problems with my VL cards.  Is this a CPU problem?

    No.  You should be sure that the motherboard is jumpered for VL bus
    clock <=33MHz.  If you still have problems you should try inserting /
    removing each of the Local Bus cards on your motherboard until the
    system works.  You may need to contact the failing adapter card
    manufacturer to see if VL bus wait states are required for their card.

12. Some of my programs work with the older CPUs but fail with my new one.
    What could cause this to occur?

    Some older benchmarks and diagnostic software do not work correctly with
    the faster processors.  If you are having problems running specific
    programs you may need to contact the respective software company to
    determine if there is an updated version of their software available.

    The AMD 80486 microprocessors are fully software compatible with
    programs written for the x86 microprocessors.

13. I would also like to know the cost and where I might purchase one, if
    not directly from AMD.

    AMD does not sell direct.  We sell our CPUs through local distribution
    companies which include Anthem Electronics, Arrow/Schweber Electronics,
    Hamilton Hallmark Electronics, Wyle Labs and Zeus Components, Inc.

    You will need to contact your local distributor directly to check on
    price, availability and length of warranty of the product you are
    interested in.

    AMD devices are also sold through the following resellers.  You should
    check to verify their pricing and the warranty that they provide with
    the devices they sell.

    Globelle            1-800-745-7000    JM Computers   1-800-331-2128
    Liuski              1-800-454-8754    PC Wholesale   1-800-723-2257
    Professional Tech.  1-800-949-5018    Riodan & Ross  1-800-727-6282
    SED                 1-800-444-8962    Solar          1-800-669-9568
    Solomon             1-800-882-9788

14. Will there be a Write-through version of the processor?

    AMD has no plans to create a write through only device at this time.
    The Am5x86-133 internal L1 cache will fully support either the write
    through or write back cache policy.

15. What would the speed comparison be if the processor was placed in a
    computer not supporting write-back caching?

    The performance for the CPU would be about 8% lower if the internal
    L1 cache is operated in write through only policy.  At the system level
    this would probably result in a 2% to 4% overall performance impact.

16. What are the benchmark numbers for the Am5x86-133 CPU?

    The benchmarks for the Am5x86-133 CPU are listed below and there is
    more information available on the AMD World Wide Web home page:

                           Am5x86-133
    
             Winstone '95 (Units)               133.0

             WinBench '96 CPUMark16             155.0

             WinBench '96 CPUMark32             161.0

    System Configuration - Gigabyte GA486AM Motherboard
                         - 256KB L2 cache (15nS)
                         - 16MB DRAM (70nS)
                         - Diamond Stealth 2 MB VRAM video card


17. Which motherboards will support the Am5x86-133 when it is released?


    MANUFACTURER     MODEL        BIOS               U.S. Contact

    Atrend           1415         Award  v3.20
                                  (10-24-95)

    Abit             PB4          Award  v4.5
                                  (11-06-95)

    Biostar          8433UUD      Award              818-443-4023
                                  UUD951102

    Gigabyte         GA486AM      Award              818-854-9338

    Holco            433          AMI                408-945-1480
                                                  (Shuttle Computer)


   FIC and Chicony should be bringing out motherboards in the first
   quarter of 1996 that support the Am5x86-133.

