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    Cayenne MXi Cyrix Corporation (with NS and IBM)
    Pentium II (Klamath) (Slot I and II) Intel
    P6 (Pentium Pro) (Socket 8) Intel
    MediaGX Cyrix Corporation
    Nx586 NexGen - AMD

    Click here to see Performance Comparision
    586 (Socket_7) PROCESSORs: MANUFACTURERs:
    Cayenne Cyrix Corporation (with NS and IBM)
    6x86MX (M2) Cyrix Corporation
    K6 AMD-NexGen (Advanced Micro Devices)
    P55C (P5-MMX) Intel
    5k86 AMD (Advanced Micro Devices)
    6x86 (M1) Cyrix Corporation
    P54C (P5) Intel

    Click here to see Performance Comparision
    Am486DX5 or AMD 5x86 AMD (Advanced Micro Devices)
    Cx5x86 Cyrix Corporation
    Cx486DX4 Cyrix Corporation
    Am486DX4 AMD (Advanced Micro Devices)
    i486DX4 Intel
    Cx486DX2 Cyrix Corporation
    Am486DX2 AMD (Advanced Micro Devices)
    i486DX2 Intel
    Cx486DX Cyrix Corporation
    Am486DX AMD (Advanced Micro Devices)
    i486DX Intel
    Cx486DLC Cyrix Corporation

    Cyrix MXi
    MXi will deliver high-performance 2D and 3D graphics, as well as the industry’s highest memory bandwidth, in an affordable solution for the mainstream desktop.
    Featuring the next-generation Cayenne core, revealed yesterday, MXi is strengthened by a dual-issue, fully pipelined floating point and MMX™ unit with 15 new multimedia floating point instructions. The processor also integrates the latest system technology, including SDRAM control, AGP and consumer-quality DVD playback, onto the processor. With its low memory latency and industry-leading memory bandwidth – greater than 2GBytes per second – the MXi is expected to significantly outperform competing non-integrated AGP solutions.
    "MXi will deliver a quantum leap in 3D, DVD and multimedia performance in an affordable, two-chip solution – just add memory," said Steve Tobak, vice president of corporate and channel marketing, Cyrix. "This chip will also provide the industry’s highest memory bandwidth, resulting in AGP performance twice that of the Pentium™ II processor."
    MXi will incorporate a complete list of state-of-the-art 3D graphics features, including bi-linear and tri-linear filtering, Alpha blending/fog, Gouraud shading, MIP mapping and Z buffering. Additionally, the MXi will be D3D® and OpenGL® compliant for mainstream software compatibility.
    With respect to performance, MXi has a 3D rendering capability of greater than 2 million triangles per second with a fill rate of 120 million pixels per second. In summary, MXi will deliver integrated, high-performance 3D processing with all the features of much more expensive multi-chip solutions.
    MXi is based on the Cayenne core, featuring a dual-issue floating point and MMX instruction unit, 64KByte L1 cache, and an enhanced sixth-generation integer unit. MXi will initially be manufactured using a .25-micron, 5-layer metal process. This includes a C4 process for flip chip assembly. As a result, the die size is expected to be about 90 mm2. With production slated for 2H98, MXi will be available in speeds rated at PR300 to PR400.

    Cyrix Cayenne
    Floating Point and MMX™ Instruction Enhancements to Deliver Industry-Leading 3D and Multimedia Performance.
    Cayenne will feature a fully pipelined, dual-issue floating point unit and 15 new multimedia floating point instructions to enable the highest-performance 3D graphics, DVD and 3D audio.
    A key component of the Cayenne core is the ability to execute four floating point operations per cycle using dual MMX instruction units. This will deliver over 1 GFLOP peak performance, a first for desktop PCs. In addition, the dual floating point reciprocal and reciprocal-square-root instructions will execute five times faster on Cayenne than on the Pentium™ II processor. These instructions are used extensively in lighting calculations for 3D image processing.
    The net result is that Cayenne will deliver in excess of 10 million meshed triangles per second to an external 3D rendering engine – more than five times faster than the Pentium II processor. Lastly, Cayenne will deliver single-cycle throughput on standard x86 floating point instructions.
    The Cayenne core will feature a dual-issue floating point and MMX instruction unit, 64KByte L1 cache, and an enhanced sixth-generation integer unit. Processors based on the core will initially be manufactured using a .25-micron, 5-layer metal process. This includes a C4 process for flip chip assembly. As a result, the core die size is expected to be about 65mm2. Processors based on this core are expected to be in production in 2H98 at speed ratings ranging from PR300 to PR400.

    Cyrix 6x86MX (M2) and M II
    The 6x86MX is the MMX version of the Cyrix 6x86 processor (code-named M2), with increased L1 cache (64 kByte) and optimized core for 32-bit softwares. The processor is Socket 7 compatible and uses dual voltage (2.9/3.3 V) power supply. Supported by most modern motherboards, however BIOS upgrade may be required. The ratio of the internal/external clock frequencies can be: 2, 2.5, 3, and 3.5. Currently 150, 166, 188, 208 and 225MHz versions are available. The processor is named after it's P-Rating performance (when it is compared to the Pentium-MMX, Pentium-Pro or Pentium-II processors). At a given internal clock rate, the 6x86MX is the fastest x86 processor around! - for example roughly 20% faster, than the
    Pentium-II. Thus the 188MHz version is named as: 6x86MX-PR233. (With the introduced new clock ratios it is easier to adjust the proper clock frequency, than in the case of older 6x86.) The processor is currently fabricated on IBM's 0.35 um technology. By August '98 the production will be moved to the National Semiconductor's new 0.25 um technology.

    Pentium II (Klamath)
    Intel's latest x86 processor (with MMX), that is NOT Socket7 compatible, consequently it can not be used in motherboards fabricated for the P54C (the old Pentium), the P55C (Pentium with MMX), or the Pentium-Pro processor. The Pentium-II is soldered onto a cartridge to be fitted into the so called "Slot One" slot of the motherboard. The Pentium II is connected to the external BSRAM (burst static RAM) on the cartridge, or in other words, the external cache is not built into the processor, like in the case of Pentium-Pro. The BSRAM clock speed is just the half of the core speed, which deteriorates the performance. To compensate this speed loss, Intel increased the internal cache memory to 2x16 kB. The possible clock frequencies: 233MHz, 266MHz and 300MHz. (There are also samples running at 400MHz.) The silicon process technology is 0.35 um and 0.28 um - at the present. Due to the high clock frequency (300MHz) and the pipelined FPU, currently the Pentium II is the fastest processor in the world for games like Quake.

    AMD K6
    The AMD-K6 processor is designed for high performance running both 16-bit and 32-bit software and to deliver performance competitive with Pentium Pro for both the Windows 95 and Windows NT(TM) operating systems. Additionally, the processor contains a fully compatible, high performance implementation of the MMX (MultiMedia eXtension) instruction set. The processor core is RISC, and designed by NexGen. K6 is Socket 7 compatible, and is manufactured using 0.35-micron, five-layer metal process technology at AMD 's state-of-the-art Fab25 manufacturing facility in Austin, Texas. Available clock rates are: 166MHz, 200MHz, 233MHz (and soon 266MHz, according to AMD). The processor requires dual voltage (2.9/3.3 V and 3.2/3.3 V for K6-PR2-233) power supply. Clock multiplier can be: 2.5, 3 or 3.5. The bus frequency jumper configurations are identical to the setup for an equivalent frequency Pentium® or P55C

    P55C (P5-MMX)
    It is an improved version of the Pentium (
    P54C) processor. It has doubled L1 cache (2x16 kB), MultiMedia eXtension (MMX), and reduced power consumption. This was the first x86 processor requiring dual voltage power supply (2.8/3.3 V). It is fabricated with Intels's 0.35 um process technology. Supported by most modern motherboards. Available clock rates: 166MHz, 200MHz and 233MHz. The processor performs well in average, however already there are faster processors for less price (K6-PR2-233 and 6x86MX-PR233).

    P6 alias "Pentium Pro"
    The Intel's Pentium® Pro processor family is for high-end desktops, workstations and servers. The family consists of processors at 150 MHz and higher and is easily scalable to up to four microprocessors in a multiprocessor system. Key Features:

  • Available at 150MHz, 166MHz, 180MHz, 200MHz and 233MHz core speeds
  • Binary compatible with applications running on previous members of the Intel microprocessor family
  • Optimized for 32-bit applications running on advanced 32-bit operating systems
  • Dynamic Execution microarchitecture
  • Single package includes Pentium® Pro processor CPU, cache and system bus interface
  • Scalable up to four processors and 4 GB memory
  • Separate dedicated external system bus, and dedicated internal full-speed cache bus
  • 8K/8K separate data and instruction, non-blocking, level one cache Available with integrated 256 KB or 512 KB, non-blocking, level two cache on package
  • Data integrity and reliability features include ECC, Fault Analysis/Recovery, and Functional Redundancy Checking
  • Upgradable to a future OverDrive® Processor

    AMD K5 (5k86)
    K5 incorporates AMD's superscalar core architecture, which combines highly efficient reduced instruction set computing (RISC) with complete x86 instruction-set compatibility. The superscalar processor capable of issuing four instructions per clock cycle­ twice as many as the Pentium (P54C).
    Pin-Compatible Pentium Alternative. The AMD-K5 processor series is designed to deliver better performance, clock-for-clock, than a Pentium. The AMD-K5 processor is compatible with the Windows standard. Tested and certified by independent compatibility and testing laboratories and licensed by Microsoft Windows Hardware Quality labs to carry the Windows logo, the AMD-K5 processor ensures compatibility with not only Windows OS but also Novell® NetWare®, OS/2 Warp, and more than 60,000 other software packages.

    Cyrix MediaGX
    The MediaGX System consists of two chips--the MediaGX processor and the MediaGX Cx5510 companion chip. This system eliminates the traditional audio and video cards, and all AT motherboard components of a PC. The MediaGX processor is a 64-bit data bus, x86-compatible processor with a proven core. The processor has 16 kB L1 cache and an FPU. The CPU directly interfaces to the PCI bus and the DRAM memory. The graphics frame buffer of the built-in sVGA (VESA 2.0) hardware is stored in main memory. Sound Blaster compatible (2x16bit stereo, 48 kHz) hardware and also integrated I/O devices (PCI, ISA, SP, PP) are incorporated in the Cx5510 companion chip. The MediaGX is fabricated with IBM's 0.35 um technology, and the processor requires 3.3-3.6 V to operate. Available clock frequencies are: 120MHz, 133MHz, 150MHz, 166MHz, 180MHz and 200 MHz. These are also the equivalent Performance Ratings, comparing to the Intel Pentium MMX processor. MMX and MPEG acceleration is also built into the MediaGX, such as USB.

    Cyrix 6x86 (M1)
    Superscalar, superpipelined processor, available in PR200+, PR166+, PR150+, PR133+ and PR120+ performance classes. Optimized to run both 16-bit and 32-bit software. It is fully compatible with the x86 instruction set and delivers very good performance running Windows® 95, Windows NT, Windows, OS/2®, DOS, Solaris UNIX® and other operating systems.
    The Cyrix 6x86 processor achieves top performance through the use of two optimized superpipelined integer units and an on-chip FPU. The 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 when executing existing non-recompiled software programs as well as future x86-compatible code. While the 6x86 achieves superior performance with existing software, it takes advantage of any recompiled code to gain an additional 5-10% performance increase.
    Superscalar architecture, Superpipelining, Register Renaming, Data Dependency Removal, Multi-Branch Prediction, Speculative Execution, Out-of-Order Completion. An 80-bit FPU provides high performance by speculatively executing FPU and integer instructions in parallel. 16-KByte Unified Write-Back Cache is incorporated. The processor is fabricated with IBM's 0.55 um and 0.45 um (6x86L) process technology. The possible clock rates: 100MHz, 110 MHz, 120MHz, 133MHz and 150 MHz.

    Superscalar Execution
    The superscalar Nx586 and Pentium processors both have two integer execution units which allow for higher performance computing.
    Harvard Architecture L1 Cache Design
    The Nx586 processor includes separate 16-Kbyte instruction and 16-Kbyte data caches compared to 8K each for the Pentium.
    Branch Prediction
    The Nx586 processor's patented branch prediction logic accurately predicts the branches in the vast majority of cases
    64-bit buses
    586-class processors employ 64-bit buses. The Nx586 processor employs 64-bit buses within the system including those between Nx586 processor and the Nx587 coprocessor, and between the Nx586 processor and the NxVL or NxPCI system logic chipset.
    RISC86 Microarchitecture
    The Nx586 processor fully implements the industry standard x86 instruction set to be able to run the more than 50,000 applications now available. This implementation is accomplished through the use of NexGen's patented RISC86 microarchitecture. The RISC86 instructions were specifically designed with direct support for the x86 architecture while obeying RISC performance principles. They are thus simpler and easier to execute than the complex x86 instructions. The RISC86 microarchitecture also contains register renaming, data forwarding, speculative execution, and out-of-order execution. The execution unit is smaller and more compact is easier to add additional execution units in future designs.
    On-chip L2 Cache Controller
    Like the Pentium Pro processor, the Nx586 processor incorporates its own level-2 cache controller directly on-chip. This assures the level-2 cache run at full speed.

    P5 (P54C) alias "Pentium"
    The Pentium processors 75MHz, 90MHz, 100MHz, and 120MHz are implemented in 3.3V, 0.6 micron technology, and the Pentium processor 133MHz, 150MHz, 166MHz and 200MHz are implemented with 3.3V, 0.35 micron technology.
    The Pentium processor family provides significant enhancements and additions including the following:
    Key Features:
  • Superscalar Architecture and Dynamic Branch Prediction
  • Pipelined Floating-Point Unit
  • Improved Instruction Execution Time
  • Separate 8K Code and 8K Data caches, Writeback MESI Protocol in the Data Cache
  • 64-Bit Data Bus, Bus Cycle Pipelining
  • Address Parity, Internal Parity Checking, Functional Redundancy Checking
  • Execution Tracing , Performance Monitoring , IEEE 1149.1 Boundary Scan
  • System Management Mode, Virtual Mode Extensions, Dual Processing Support
  • SL Power Management Features, Fractional Bus Operation, On-Chip Local API

    AMD 5x86 or AMD 486DX5
    Actually a 486 processor, that uses 4 times higher internal clock frequency than the external. (It would be logical to use the name: DX4, but it was already engaged.)
  • clock frequencies: 25/100 or 33/133 and 50/150 or 40/160 MHz
  • 16 kByte integrated on chip L1 cache RAM, write back mode!
  • 3.3 V operation
    The fastest processors that we can put into a 486 motherboard is the Cyrix
    5x86/120MHz and the AMD 5x86/160MHz processors. They perform comparably to the Pentium-90 MHz processor.

    Cyrix 5x86 (M1sc)
    The lite version of the
    M1 processor with a 32 bit interface that enables the chip to operate in 486 motherboards. This chip got the name: 5x86.
    Features summary:
  • clock frequencies: 33/100 or 50/100 and 40/120 MHz
  • 16 kByte integrated on chip L1 cache RAM, write back mode, two way associative
  • 30% faster CPU at a given clock rate, than a 486DX4 processor
  • 40% faster FPU at a given clock rate, than a 486DX4 processor
  • 3.6 V operation
  • often operates in the same "jumper environment" than i486DX4!
    The fastest processors that we can put into a 486 motherboard is the Cyrix 5x86/120MHz and the AMD 5x86/160MHz processors. They perform comparably to the Pentium-90 MHz processor.

    Cyrix 486DX4
    Cyrix has started relatively lately the production of its 486DX4 family processors. What is more, the processors often used strange voltage settings, like 4 V. The available
  • clock frequencies: 25/75 or 40/80 and 33/100 or 50/100 MHz
  • 8 kByte integrated on chip L1 cache RAM, that sometimes works just in write through mode (in the case of BIOS incompatibility)
  • about 10% faster FPU than Intel's
  • 3.6 or 4 V operation Notice:
    This time Cyrix focused all its effort to develop the
    5x86 (M1sc) and 6x86 (M1) processors.

    AMD 486DX4
    AMD has also started the production of it's DX4-line processors:
  • clock frequencies: 25/75 or 40/80, and 33/100 or 50/100 MHz
  • 8 kByte integrated on chip L1 cache RAM, write trhough mode instead of write back (15% speed loss!)
    Later AMD developed an advanced Am486DX4 processor (SV8B):
  • clock frequency: 40/120 MHz
  • 16 kByte integrated on chip L1 cache RAM, write back mode!
  • 3.3 V operation

    486DX4 (Intel)
    The first
    Pentiums (P5) were NOT fast enough to substantially shine out the fastest 486DX2/80MHz machines. This was caused by the relatively SLOW system bus (VLB, or PCI), and the write through operation of the internal cache memory. Maybe this forced Intel to develope the i486DX4/100MHz processor, which soon became the next standard. This processor easily outperformed a P5-60 MHz processor equipped PC.
  • clock frequencies: 25/75 or 40/80, and 33/100 or 50/100 MHz
  • 16 kByte integrated on chip L1 cache RAM, write back
  • 3.3 V operation

    Cyrix 486DX2
    Cyrix has started relatively lately the production of its 486DX2 family processors. What is more, the processors often used strange voltages, like 4 V. The available
  • clock frequencies: 25/50, 33/66, 40/80 MHz
  • 8 kByte integrated on chip L1 cache RAM, that sometimes works just in write through mode (in the case of BIOS incompatibility)
  • about 10% faster FPU than Intel's
  • 3.6, 4, or 5 V operation

    AMD 486DX2
    AMD has lost the legal action against Intel and had to stop producing 486DX, 486DX2/50 and 486DX2/66 processors. Fortunately for AMD, Intel didn't produce 80 MHz version of the 486DX2 processor, consequently AMD was allowed to fabricate it:
  • frequency: 40/80 MHz
  • 8 kByte integrated on chip L1 cache RAM, write through (10% slower than write back).
    With higher operating frequency, the difference between the write through and write back cache mode are more expressed. Therefore the Am486DX2/80 MHz processor is just a little bit faster than the i486DX2/66 MHz.

    486DX2 (Intel)
    Several years ago Intel developed the 486DX/33MHz processor, which could provide the necessary processing power for the MicrosoftTM Windows operating system, well, at a basic level. Looking for the way of further improvement, Intel has increased the clock rate of the processor up to 50 MHz. However, that processor was NOT a success, because in the lack of sufficiantly fast external cache memory, it caused unreliable operation. Intel decided to find another solution, and succeeded! They created the 486DX2 processor, which run at 33 MHz external, but 66 MHz internal. In other words, the processor doubles the external frequency. The effectivity of this construction is obviously depends very much on the internal (L1) cache size and mode (write through or write back). At the same time, the role of the external cache memory is somewhat smaller. Dispite the great success of the 486DX2/66MHz processor, Intel was not ambitious to develop (on a similar basis) a 486DX3/100MHz processor. The available clock
  • frequencies are: 25/50 and 33/66 MHz
  • In a good motherboard 40/80 MHz operation of the 33/66 MHz processor is usually possible.
  • 486DX2/66MHz processor is a minimum, if You use NetScape Navigator 3.0 on Windows 3.1x (or Windows95) through a 14.4k modem.
  • At this time Intel has started to develop the Pentium (P5) processor, and the PCI BUS which supposed to be a general solution for the interfacing problems between the processor, the memory and the external devices.

    Cyrix 486DX
    This processor is compatible with Intel's
    i486DX processor, and provides similar performance too. The inside construction of the processor is original Cyrix design. This may cause incompatibility issues in certain motherboards, namely the L1 cache (which is write back) can only be used in write through mode (5% slower). Different characteristics of the Cx486DX:
  • 8 kByte integrated on chip L1 cache RAM, sometimes works just in write through mode
  • clock frequencies: 25, 33, 40 MHz
  • about 10% faster FPU than Intel's

    AMD 486DX
    This processor is compatible with Intel's
    i486DX processor, and provides similar performance too. What is more, the inside constructions of the processors are also similar, which led Intel and AMD to litigation. Different characteristics of the Am486DX:
  • 8 kByte integrated on chip L1 cache RAM, write through (5% slower than write back).
  • clock frequencies: 33, 40 MHz

    486DX (Intel)
    Not long ago the most favorit 32 bit, x86 compatible processor family. All the 486 processors have an integrated on chip L1 cache, and usually integrated FPU (floating processor unit) too. The data path to RAM is 32 bit wide. The maximum addressable operating memory is 1 MByte (in real address mode), or 1 GByte (in protected virtual mode). External cache memory and mathematical co-processor can be applied (i80487DX). Many types of the 486 processor family are available with different clock rates, on chip L1 cache and with or without FPU. Their common features are as follows:
  • 32 bit, x86 compatible core
  • 32 bit wide data path to operating RAM
  • 8 kByte integrated on chip L1 cache RAM, write back operation
    +The differences between the types:
  • clock frequencies: 16, 20, 25, 33, 50 MHz
  • 486SX types have NO FPU

    Cyrix 486DLC
    This processor was designed by Cyrix to provide a cheap alternative instead of Intel's
    i486DX processor. The 486DLC processor performes much better than a 386DX at the same clock rate, however, it is slower than a "real" 486DX processor. (Especially true for the FPU unit.) In general usage a 40MHz/486DLC worth a 33MHz/486DX. It should be noted, that for Windows 3.1x at least a 40MHz/486DLC, or 33MHz/486DX required for acceptable performance.
  • clock frequencies: 33, 40 MHz
  • 1 kByte integrated on chip L1 cache RAM
  • external FPU, Cx487DLC (Intel 387 compatible, but 10% faster)

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