Processor Specifications

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<ul><li> 1. Processor Specifications Many confusing specifications often are quoted in discussions of processors. The following sections discuss some of these specifications, including the data bus, address bus, and speed. The next section includes a table that lists the specifications of virtually all PC processors. Processors can be identified by two main parameters: how wide they are and how fast they are. The speed of a processor is a fairly simple concept. Speed is counted in megahertz (MHz), which means millions of cycles per secondand faster is better! The width of a processor is a little more complicated to discuss because there are three main specifications in a processor that are expressed in width. They are Internal registers Data input and output bus Memory address bus Systems below 16MHz usually had no cache memory at all. Starting with 16MHz systems, high-speed cache memory appeared on the motherboard because the main memory at the time could not run at 16MHz. Prior to the 486 processor, the cache on the motherboard was the only cache used in the system. Starting with the 486 series, processors began including what was called L1 (Level 1) cache directly on the processor die. This meant that the L1 cache always ran at the full speed of the chip, especially important when the later 486 chips began to run at speeds higher than the motherboards they were plugged into. During this time the cache on the motherboard was called the second level or L2 cache, which ran at the slower motherboard speed. Starting with the Pentium Pro and Pentium II, Intel began including L2 cache memory chips directly within the same package as the main processor. Originally this built-in L2 cache was implemented as physically separate chips contained within the processor package but not a part of the processor die. Since the speed of commercially available cache memory chips could not keep pace with the main processor, most of the L2 cache in these processors ran at one-half speed (Pentium II/III and AMD Athlon), while some ran the cache even slower, at two-fifths or even one-third the processor speed (AMD Athlon). The original Pentium II, III, Celeron, and Athlon (Model 1 and 2) processors use 512KB of either one-half, two-fifths, or one-third speed L2 cache as Table 3.1 shows:Table 3.1 L2 Cache Speeds</li></ul><p> 2. ProcessorSpeedL2L2 TypeL2 Speed512KBExternal1/2 core (225300MHz)512KBExternal1/2 core (275350MHz)512KBExternal2/5 core (300340MHz)512KBExternal1/3 core (300333MHz)SizePentium III450 600MHzAthlon550 700MHzAthlon750 850MHzAthlon900 1000MHzThe Pentium Pro, Pentium II/III Xeon, newer Pentium III, Celeron, K6-3, Athlon (Model 4), and Duron processors include full-core speed L2 as shown in Table 3.2.Table 3.2 Full-Core Speed Cache ProcessorSpeedL2 SizeL2 typeL2 SpeedPentium Pro150256KBExternalFull core200MHz1MB350256KBOn-dieFull core64KBOn-dieFull coreK6-3450MHzDuron550 700+MHz 3. ProcessorSpeedL2 SizeL2 typeL2 SpeedCeleron300128KBOn-dieFull core400512KBExternalFull core450MHz2MB650256KBOn-dieFull core256KBOn-dieFull coreOn-dieFull core600+MHzPentium II XeonAthlon1000+MHzPentium III500 1000+MHzPentium III500256KBXeon1000+MHz2MBThe problem originally forcing the L2 cache to run at less than the processor core speed was simple: The cache chips available on the market simply couldn't keep up. Intel built its own high-speed cache memory chips for the Xeon processors, but it also made them very expensive. A breakthrough occurred in the second-generation Celeron, where Intel built both the L1 and L2 caches directly on the processor die, where they both ran at the full-core speed of the chip. This type of design was then quickly adopted by the second generation Pentium III, as well as the AMD K6-3, Athlon, and Duron processors. In fact virtually all future processors from Intel and AMD have adopted or will adopt on-die L2 cache as it is the only cost-effective way to include the L2 and bring the speed up. Table 3.3 lists the primary specifications for the Intel family of processors used in IBM and compatible PCs. Table 3.4 lists the Intel-compatible processors from AMD, Cyrix, NexGen, IDT, and Rise. NOTE 4. Note in Table 3.3 that the Pentium Pro processor includes 256KB, 512KB, or 1MB of full-core speed L2 cache in a separate die within the chip. The Pentium II/III processors include 512KB of 1/2 core speed L2 cache on the processor card. The Celeron, Pentium II PE, and Pentium IIIE processors include full-core speed L2 cache integrated directly within the processor die. The Celeron III uses the same die as the Pentium IIIE, however half of the on-die cache is disabled, leaving 128KB functional. The transistor count figures do not include the external (off-die) 256KB, 512KB, 1MB, or 2MB L2 cache built in to the Pentium Pro, Pentium II/III, Xeon, or AMD Athlon CPU packages. The external L2 cache in those processors contains an additional 15.5 (256KB), 31 (512KB), 62 million (1MB), or 124 million (2MB) transistors in separate chips! Note in Table 3.4 that the Athlon includes either 512KB of L2 cache via separate chips, running at either one-half, two-fifths, or one-third the core speed, or 256KB of on-die L2 running at full-core speed, depending on which version you have.Processor Speed Ratings A common misunderstanding about processors is their different speed ratings. This section covers processor speed in general, and then provides more specific information about Intel processors. A computer system's clock speed is measured as a frequency, usually expressed as a number of cycles per second. A crystal oscillator controls clock speeds using a sliver of quartz sometimes contained in what looks like a small tin container. Newer systems include the oscillator circuitry in the motherboard chipset, so it might not be a visible separate component on newer boards. As voltage is applied to the quartz, it begins to vibrate (oscillate) at a harmonic rate dictated by the shape and size of the crystal (sliver). The oscillations emanate from the crystal in the form of a current that alternates at the harmonic rate of the crystal. This alternating current is the clock signal that forms the time base on which the computer operates. A typical computer system runs millions of these cycles per second, so speed is measured in megahertz. (One hertz is equal to one cycle per second.) An alternating current signal is like a sine wave, with the time between the peaks of each wave defining the frequency (see Figure 3.1). Figure 3.1 Alternating current signal showing clock cycle timing. NOTE The hertz was named for the German physicist Heinrich Rudolf Hertz. In 1885, Hertz confirmed the electromagnetic theory, which states that light is a form of electromagnetic radiation and is propagated as waves. 5. A single cycle is the smallest element of time for the processor. Every action requires at least one cycle and usually multiple cycles. To transfer data to and from memory, for example, a modern processor such as the Pentium II needs a minimum of three cycles to set up the first memory transfer and then only a single cycle per transfer for the next three to six consecutive transfers. The extra cycles on the first transfer are normally called wait states. A wait state is a clock tick in which nothing happens. This ensures that the processor isn't getting ahead of the rest of the computer.Table 3.3 Intel Processor Specifications ProceCPVoltInterDaMaxLevL1LevL2InteMultiNo. ofDatessorUagenalta.el 1Cael 2CagralmediaTransiIntrodClRegiBuMeCaccheCacheFPInstrustorsucedocstersmorheTycheSpUctionskSizeWiy29,00June0197929,00June01978134,0Feb.001982275,0June001988855,0Oct.001990275,0Oct.001985peeedth8088386D X1x1x5v3.3v5v16-16-1Mbit16-16Mbit16-16MbitB32-16-16M0KBbitB132-32-4GBbitbitB32-B16-Bbit386SL1x5vbitbit386SX1x1Mbit2865v8-bit1x5v16bit80861xdBusWTBusBu s 6. ProceCPVoltInterDaMaxLevL1LevL2InteMultiNo. ofDatessorUagenalta.el 1Cael 2CagralmediaTransiIntrodClRegiBuMeCaccheCacheFPInstrustorsucedocstersmorheTycheSpUctionskSizeWiy1.185AprilM19911.185AprilM19941.2MAprilpeeedth486SX487SX486D5vX486SL1x3.3v2486D2x5vX232-32bit32-32bit32-32bit32-32-bit1x5vbitbit1x32-bit232-4GB8KBWTbitbit5v32-bit2x5v32bit486SX1xdbitBu s4GB8KBWTBus4GB8KBWTBuYess4GB8KBWTBu1991Yes1.2Ms4GB8KBWTBu1989Opt.1.4Ms4GB8KBWTBuAprilNov. 1992Yes1.2MsMarc h 1992486D2X43x486Pe2.5ntium3.3v32-bit5v32-bit32-32-4GB16KWTB4GB2x1BuYes1.6MsWBBuFeb. 1994Yes3.1MJan. 7. ProceCPVoltInterDaMaxLevL1LevL2InteMultiNo. ofDatessorUagenalta.el 1Cael 2CagralmediaTransiIntrodClRegiBuMeCaccheCacheFPInstrustorsucedocstersmorheTycheSpUctionskSizeWiypeeedthODxPentiu1xbitmbit32-64-bit5vd6KBbit4GB2x8sWBKBBu1995Yes3.1MsMarc h60/661993Pentiu1.53.332-64-4GB2x8m 75bitbit2003x1.51.832-64-mbitbitMMX4.564-64G2x8bitbitBKBKB4GB2x1BuYes2.8v32-3.5vPentiuWB3.3MsWB6KBBuOct. 1994YesMMX4.5MsJan. 1997xPentiu2m Pro3.3v3xWB256CorKBYes5.5MeNov. 1995512 KB 1M BPentiu3.51.832-64-64G2x1m IIbitbitB6KB4.5WB512?KBCorYesMMX7.5MMay 1997 8. ProceCPVoltInterDaMaxLevL1LevL2InteMultiNo. ofDatessorUagenalta.el 1Cael 2CagralmediaTransiIntrodClRegiBuMeCaccheCacheFPInstrustorsucedocstersmorheTycheSpUctionskSizeWiyYesMMX27.4MJan.peeedthx2.8vPentiu3.51.6vm IIPE6xCelero3.5nde32-64-64G2x1bitbitB6KB1.832-64-64G2x1bitbitB6KB4.5WBCorKB2.8vWB256e0K19993YesMMX7.5MBApril 1998xCelero3.51.532-64-64G2x1nA2vbitbitBWB6KB128CorKBe128CorKBe512?KBCorYesMMX19MAug. 199838xCelero4.51.332-64-64G2x1n IIIbitbitB6KB9x1.6vPentiu41.832-64-64G2x1m III6x2vbitbitB6KBWBWBYesSSEeYesSSEFeb.4328.1M20009.5MFeb. 1999 9. ProceCPVoltInterDaMaxLevL1LevL2InteMultiNo. ofDatessorUagenalta.el 1Cael 2CagralmediaTransiIntrodClRegiBuMeCaccheCacheFPInstrustorsucedocstersmorheTycheSpUctionskSizeWiyYesSSE28.1MOct.peeedthdPentiu41.332-64-64G2x1m IIIE9xbitbitBWB6KB256CorKBe512CorKBe199931.7vPentiu41.832-64-64G2x1m II4.5bitbitB6KBXeonxWB2.8vYesMMX7.5MApril 19981M B 2M BPentiu51.832-64-64G2x1m III6xbitbitB6KBXeonWBCorKB2.8v512YesSSE9.5MeMarc h1M1999B 2M BPentiu4.51.632-64-64G2x1WB256Corm IIIE5vbitbitB6KBKBeXeon6.51MxB 2M B3YesSSE28.1MOct.84M1999140MMay 2000 10. Table 3.4 AMD, Cyrix, NexGen, IDT, and Rise Processors ProcesCVoltInteDaMaLevL1LeL2InteMultiNo.DatesorPagernaltax.el 1CavelCagralmediofIntroURegBuMeCacch2chFPaTransduceClistersmorheeCaeUInstruistorsdocSizWiyTychSpkedtpeeee4.3MMarhdAMD1.3.532-644G16+WK55vbit-B8KB1.ctionsbitBuYess1996B75 xAMD2.2.232-644G2x3WK65bit-B2KB4.3.25xvAMD2.1.932-644G2x3WK6-25bit-B2KB6x2.4bitBuYesMMX8.8MsApril 1997BbitBuYess3DNo9.3MwMay 1998BvAMD3.1.832-644G2x3W25CoK6-35bit-B2KB6Kre4.2.45xvbitBB3Yes3DNo21.3Feb.wM1999 11. ProcesCVoltInteDaMaLevL1LeL2InteMultiNo.DatesorPagernaltax.el 1CavelCagralmediofIntroURegBuMeCacch2chFPaTransduceClistersmorheeCaeUInstruistorsdocSizWiyTychSpkedtpeeee22MJun.hAMD51.632-64Athlon10bitx1.8ctionsd8TB2x6W511/2-4KB2K3DNobitBB1/3wvYesEnh.1999Co reAMD51.532-64Duron10bitx1.88TB2x6W64Co-4KBKBrebitYesBEnh.25M3DNo3Jun. 2000wvAMD51.532-64Athlon10bit4x1.8(Thun8TB2x6W25Co-4KB6KrebitBYesEnh.37M3DNo3BJun. 2000wvderbird )Cyrix 6x862x2.532-644G16KWbit-BBB3.5 vbitBu sYes3MFeb. 1996 12. ProcesCVoltInteDaMaLevL1LeL2InteMultiNo.DatesorPagernaltax.el 1CavelCagralmediofIntroURegBuMeCacch2chFPaTransduceClistersmorheeCaeUInstruistorsdocSizWiyTychSpkedtpeeee6.5MMayhctionsdCyrix22.232-644G64KW6x86M3.bit-BBBX/MII5x2.9BuYesMMXs1997bitvCyrix2.2.232-644G64KW25CoIII5vbit-BBB6Kre7xNexGe2xbit4v32-644G2x1W-B6KBNx586bit33.332-644G2x3WWinchi4xbit-B2KwFeb 2000BuYes3.5MsB3.522MMar 1994BIDTp3DNoBbitnYes3bitBuYesMMX5.4MsOct. 1997BvIDT2.3.332-644G2x3WWinchi33bit-B2KBp2/2A3.54xvbitBBu sYes3DNo w5.9MSept. 1998 13. ProcesCVoltInteDaMaLevL1LeL2InteMultiNo.DatesorPagernaltax.el 1CavelCagralmediofIntroURegBuMeCacch2chFPaTransduceClistersmorheeCaeUInstruistorsdocSizWiyTychSpkedtpeeee3.6MOct.hdRise22.832-644G2x8WmP63.vbit-BKBB5xctionsBuYesMMXs1998bitFPU = Floating-Point Unit (internal math coprocessor) WT = Write-Through cache (caches reads only) WB = Write-Back cache (caches both reads and writes) Bus = Processor external bus speed (motherboard speed) Core = Processor internal core speed (CPU speed) MMX = Multimedia extensions, 57 additional instructions for graphics and sound processing 3DNow = MMX plus 21 additional instructions for graphics and sound processing Enh. 3DNow = 3DNow plus 24 additional instructions for graphics and sound processing SSE = Streaming SIMD (Single Instruction Multiple Data) Extensions, MMX plus 70 additional instructions for graphics and sound processing The time required to execute instructions also varies: 8086 and 8088. The original 8086 and 8088 processors take an average of 12 cycles to execute a single instruction. 286 and 386. The 286 and 386 processors improve this rate to about 4.5 cycles per instruction. 14. 486. The 486 and most other fourth-generation Intel compatible processors such as the AMD 5x86 drop the rate further, to about two cycles per instruction. Pentium, K6 series. The Pentium architecture and other fifth-generation Intel compatible processors such as those from AMD and Cyrix include twin instruction pipelines and other improvements that provide for operation at one or two instructions per cycle. Pentium Pro, Pentium II/III/Celeron and Athlon/Duron. These P6 class processors, as well as other sixth-generation processors such as those from AMD and Cyrix, can execute as many as three or more instructions per cycle. Different instruction execution times (in cycles) make it difficult to compare systems based purely on clock speed or number of cycles per second. How can two processors that run at the same clock rate perform differently with one running "faster" than the other? The answer is simple: efficiency. The main reason why the 486 was considered fast relative to a 386 is that it executes twice as many instructions in the same number of cycles. The same thing is true for a Pentium; it executes about twice as many instructions in a given number of cycles as a 486. This means that given the same clock speed, a Pentium will be twice as fast as a 486, and consequently a 133MHz 486 class processor (such as the AMD 5x86-133) is not even as fast as a 75MHz Pentium! That is because Pentium megahertz are "worth" about double what 486 megahertz are worth in terms of instructions completed per cycle. The Pentium II and III are about 50 percent faster than an equivalent Pentium at a given clock speed because they can execute about that many more instructions in the same number of cycles. Comparing relative processor performance, you can see that a 1000MHz Pentium III is about equal to a (theoretical) 1,500MHz Pentium, which is about equal to an 3,000MHz 486, which is about equal to a 6,000MHz 386 or 286, which is about equal to a 12,000MHz 8088. The original PC's 8088 ran at only 4.77MHz; today, we have systems that are comparatively about 2,500 times faster! As you can see, you have to be careful in comparing systems based on pure MHz alone, because many other factors affect system performance. Evaluating CPU performance can be tricky. CPUs with d...</p>


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