 SU.HARDW.PC.CPU (2:5020/299)  SU.HARDW.PC.CPU 
 From : Sergey Kutikin                      2:5020/324.16   Sat 08 Jun 96 19:32 
 Subj : Cx6x86 FAQ (part 1)                                                     

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                              Cyrix Processors

            Frequently Asked Questions about the 6x86 Processor

Q. What is the Cyrix 6x86 processor?

     A. The sixth-generation 6x86 processor, formerly the M1, is a
     high-performance superscalar, superpipelined, x86 processor.

Q. Why is Cyrix, a microprocessor manufacturer, selling PCs?

     A. We want people to know about the outstanding performance advantages
     of the Cyrix 6x86 processor. Marketing 6x86 PC systems is a key
     element in promoting Cyrix processors to end users, thus promoting
     demand for our OEM customers' 6x86-based PCs.

Q. Will Cyrix continue selling processors to OEMs?

     A. Yes. The vast majority of Cyrix processors will be sold to OEMs and
     PC dealers who will market 6x86-based PCs under their own brand.

Q. How does it differ from the Pentium processor?

     A. Most significant are the architectural differences which result in
     the 6x86 processor's superior performance gains. While both the 6x86
     and Pentium processors are superscalar and contain an 80-bit floating
     point unit and a 16-KByte primary cache, other architectural features
     are found only on the 6x86. The 6x86 processor's integer and floating
     point units are optimized for maximum instruction throughput by using
     advanced architectural techniques including register renaming,
     out-of-order completion, data dependency removal, branch prediction
     and speculative execution. These design innovations eliminate many
     data dependencies and resource conflicts to achieve high performance.

Q. What is the difference between the Cyrix 6x86 and 5x86 processor?

     A. There are significant differences between these two Cyrix
     processors. The 5x86 processor, formerly the M1sc, is pin-compatible
     with a 486. However, the 5x86 uses many fifth-generation features
     (branch prediction, data forwarding, superpipelining, etc.) to achieve
     performance equal to Pentium processors. The goal for the 5x86 was to
     achieve an efficient design, obtaining the highest performance
     possible using the fewest transistors to obtain entry-level Pentium
     processor performance. A 120 MHz 5x86 performs on par with a 90 MHz
     Pentium processor.

     The Cyrix 6x86 processor is a high-performance, sixth-generation CPU
     that is P54C socket-compatible. It incorporates a 64-bit external data
     bus (5x86 use a 32-bit external data bus) and a variety of innovative
     architectural features that enable it to outperform higher-megahertz
     Pentium processors to achieve best-in-class performance. Additional
     design information can be found in the 6x86 Processor Brief.

Q. Can I use the Cyrix 6x86 processor as an upgrade for my 586 computer?
     A. Cyrix doesn't sell the 6x86 processor as an upgrade processor.
     However, some dealers or resellers may offer a 6x86 upgrade solution.

Q. Will future 6x86 processors work in the 6x86-based PC I buy today ?
     A. Yes.Cyrix offers users of 6x86-based PCs an easy path to higher
        perfomance for Windows NT and to MMX technology that protects
        today's PC investments.The next version of Cyrix's 6x86 processor,
        code-named M2,will provide optimum perfomance on 32-bit software
        and will be fully MMX compatible.This new processor will leverage
        today's 6x86 motherboard platforms,allowing plug-in upgrades for
        today's buyers of 6x86-based PCs.Purchasers can buy a 6x86-based
        PC now,with a guaranteed path to future technology via an M2 upgrade. 

Q. Is the 6x86 processor compatible with existing software?

     A. Yes. The 6x86 is compatible with x86 software and all popular x86
     operating systems including Windows 95, Windows, Windows NT, OS/2,
     DOS, Solaris and UNIX. Additionally, the 6x86 processor has been
     certified Windows 95 compatible by Microsoft.

Q. Is the Cyrix 6x86 processor certified for Windows 95?

     A. Yes. Cyrix tested the 6x86 processor on  [Designed for Windows 95]
     hundreds of x86 software applications to
     ensure compatibility with new and existing software. Additionally, the
     6x86 processor has been certified Windows 95 compatible by Microsoft.
     We're licensed by Microsoft to use the "Designed for Windows 95" logo.

Q. Can the 6x86 processor run 16-bit and 32-bit software?

     A. Yes. The 6x86 was designed to run existing 16-bit software as well
     as the latest 32-bit software.

Q. What are the performance results for the 6x86 processor?

     A. We list full, competitive 6x86 performance results for several
     industry benchmarks. The tests show that the 6x86 processor
     outperforms higher-megahertz Pentium processors in each performance
     class.

Q. What is this new performance, or P-rating, system Cyrix is using?

     A. The P-rating system was jointly developed by Cyrix, IBM
     Microelectronics, SGS-Thomson Microelectronics, and Advanced Micro
     Devices. The P-rating system allows end-users to base purchases on
     relative PC performance levels rather than just the clock speed (MHz)
     of the processor. The new evaluation system relates the results of
     industry-standard benchmarks to what is achieved by an Intel Pentium
     processor of a given frequency. For example, a processor with a P150
     rating would have performance comparable to a 150 MHz Pentium
     processor, regardless of its actual clock speed.

Q. Why was the P-rating developed?

     A. Clock frequency (MHz), while important, is no longer an accurate or
     consistent measure of CPU performance. Architectural differences
     between processor designs add another variable to the equation. With
     the P-rating in place, a PC buyer can easily evaluate all personal
     computer processors for a given performance category -- without
     scrutinizing the architectural merits of the different processors.

     MicroDesign Resources (MDR) Labs conducted independent performance
     testing of the 6x86 processor. Commenting on the P-rating methodology,
     Michael Slater, president of MicroDesign Resources and publisher of
     the Microprocessor Report, said, "This is the first comprehensive and
     credible method for comparing competing processors based on the
     relative performance they bring PC users under real-world conditions.
     It standardizes test system configurations based on commercially
     available components, and it uses the most widely recognized and
     utilized application-based benchmark tests. I expect the new P-rating
     methodology to achieve broad industry acceptance."

Q. How does the P-rating work?

     A. The P-rating process uses a standardized system configuration and
     application-based benchmark tests to establish a performance, or 'P,'
     rating relative to a Pentium processor of a given frequency (MHz).
     This levels the playing field and allows the measurement of relative
     processor performance under real-world conditions, regardless of the
     processor's clock speed (MHz) or architecture.

Q. What benchmark test is used in the P-rating?

     A. Ziff-Davis Winstone 96 is used because it is a real-world,
     application-based benchmark that contains the most popular software
     applications (based on market share) that run on a Pentium processor.
     Winstone 96 also is the most widely used benchmark, and is freely
     distributed and available.

Q. Why is there a plus mark in each 6x86 processor name?

     A. For the 6x86 processor, a P+ designation is used to indicate better
     performance.

                Winstone 96 6x86-Pxxx+ > Winstone 96 Pentium-xxx
                       xxx = P-rating or Pentium megahertz

     For example, a 6x86 processor with a P-rating of "P166+" (regardless
     of processor name and clock speed) indicates performance faster than a
     166 MHz Pentium processor. The plus mark indicates performance that
     consistently exceeds the same Pentium processor megahertz level.

Q. What 6x86 processors are currently available ? 
     A. The 6x86-P166+(133 MHz),6x86-P150+(120 MHz),6x86-P133+(110 MHz) and
        6x86-P120+(100 MHz) processors are in volume production now.Volume
        production of the 6x86-P200+(150 MHz) is planned for August.
         
Q. What if I have more questions?
     A. Please contact the Cyrix Processor Support Desk.

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                       6x86 Processor Technical FAQs

Q.What does the C028, 3.52V (C028), or 3.52V mark on top of the chip mean?

     A. C028 or 3.52V (028): The device operates at a nominal voltage of
     3.52V. You should use the appropriate voltage settings on the
     motherboard (often documented as VRE, 3.52V or 3.4-3.6V range). C016
     or 3.3V (016): The device operates at a nominal voltage of 3.3V. You
     should use the appropriate voltage settings on the motherboard.

Q.What does the 110MHz on the 6x86-P133 chip mean?

     A.The operating frequency is 110MHz (55MHz bus) but the device has
     been verified to perform better than a Pentium-133.

Q.Which motherboards work with the 6x86?

     A. Refer to the Cyrix recommended 6x86 motherboard list for
     information on P166+ certified platforms.

Q.I have found other motherboards that work with the 6x86 but are not on
  your recommended list. Why not?

     A.It could be one of several things: the manufacturer has not given us
     a sample, has not approved the listing, or it is going through testing
     now, but has not completed the test suite.

Q.How do I know my motherboard can support the 55/110 MHz 6x86-P133?

     A.The board or documentation should have jumper settings defined for
     55/110MHz. Refer to the Cyrix recommended 6x86 motherboard list for a
     complete list of platforms that support the P133+.

Q.What board MHz setting do I use for each P-rating?

     A.P120+ = 50MHz CPU bus with a 2X clock (50/100MHz)
       P133+ = 55MHz CPU bus with a 2X clock (55/110MHz)
       P150+ = 60MHz CPU bus with a 2X clock (60/120MHz), same as Pentium-120
       P166+ = 66MHz CPU bus with a 2X clock (66/133MHz), same as Pentium-133
       P200+ = 75MHz CPU bus with a 2X clock (75/150MHz)

Q.The motherboard has several voltage settings. Which one is right for the
  6x86?

     A.It depends on which CPU you have. The markings on top of chip will
     indicate which voltage setting is appropriate.

Q.Why does the BIOS recognize my 6x86-P133 chip as a 6x86-P120?

     A.The motherboard jumpers are incorrectly set to 50/100MHz or the
       motherboard does not support 55/110MHz.

Q.Does Cyrix ship a cooling fan/heatsink with the 6x86 processor?

     A.Yes, each processor is shipped with a certified heatsink/fan. We do
       this to guarantee a quality heatsink/fan is in use to ensure proper
       operation of the CPU.

Q.Why does the processor get hot?

     A.The CPU may have an inadequate heatsink/fan. The certified
     heatsink/fan we ship with each processor is guaranteed to keep the CPU
     temperature within the specifications.

Q.The Cyrix cooling fan doesn't fit on my boards. What do you recommend?

     A.The Cyrix certified heatsink/fan should work in most boards.
     However, Cyrix can ship the CPU without a heatsink/fan if you would
     like to find your own heatsink/fan to fit on board. If the clip is a
     problem (components too close to socket 7), use the Cyrix verified
     heatsink/fan solution available from VEMALINE that slides onto the CPU
     package (Part No. HTS108). Another alternative is to use a different
     motherboard. Refer to the Cyrix recommended 6x86 motherboard list for
     more information.

Q.Does Cyrix have a heatsink/fan solution that is 90 degrees oriented so
  the voltage regulator can be cooled?

     A.Cyrix recommends having an adequate heatsink on the voltage
     regulator. If further cooling is deemed necessary, the VEMALINE HTS108
     solution can be used. This solution can be oriented to blow air to the
     voltage regulator.

Q. When I run Windows 95 on my 6x86 computer, the Windows 95 control panel
   system information identifies the CPU as a 486. Why?

     A. The algorithm used in Windows 95 to detect the CPU was completed
     before the Cyrix 686 was released and therefore the Cyrix 686 responds
     to the algorithm just as a 486 does. To verify that your system is
     using the 6x86 microprocessor, please reference your computers BIOS
     startup screen. In addition, the following software utilities identify
     the 6x86 CPU correctly: Diagsoft QA Factory 6.02 and QA Plus/FE 5.42;
     Quarterdeck Manifest 4.01; and PC Doctor Rev 1.5.162 from Watergate
     Software. Cyrix will update this site with new software utilities that
     can detect a 6x86 CPU in the future. Please note that the 6x86
     processor was certified by Microsoft for Windows 95, and Windows 95
     performance results are available.

Q. When I run 3D Studio and Clipper on my 6x86-based PC, the programs are
   stalling. What's the solution?

     A. Both 3D Studio and Clipper Applications use software timing loops
     in the code. The 6x86 processor executes these loop instructions
     faster than previous x86 CPUs which interferes with timing dependent
     code in both software programs. Solution: Download the pipeloop.exe
     file and put it in your autoexec.bat file. This utility inserts a
     delay in the loop instruction. The utility is not memory resident.
     NOTE: This file may not correct all timing issues. Other solutions
     will be listed when available.
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     Copyright (c) 1995-1996 by Cyrix Corporation. Updated June 6, 1996,
                           Richardson, TX, U.S.A.

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                                               Best regards,Sergey 
--- GEcho 1.11+
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