Chapter5:RAMWhatisRAM?Theterm'RAM'isanacronymforRandomAccessMemory,thisisthememorythatyourcomputerusestorunitsoperatingsystemandanyapplicationsthatyoustart.Thenamemeansthatthecomputercanaccessinformationheldanywhere(i.e.atarandomlocation)inRAMbyaddressingthatpartoftheRAMdirectly.Inotherwordsifthereissomeinformationstoredinthe1000thlocationinmemorythesystemdoesnothavetoreadtheinformationinthepreceding999locationstogetthere,insteaditcanaccessthe1000thlocationsimplybyspecifyingit.Thealternativewouldbecalledsequentialaccess,anexampleofwhichwouldbeaccessinginformationstoredonaharddrive-thedrivecanonlyreadtheinformationwhichiscurrentlypassingunderneaththeread/writeheads,soifanapplicationwantsinformationinsaysector14ofacertaintrackthedrivehasnooptionbuttoreadalltheinformationonthattrack.Thedriveelectronicsthenseparatesouttheinformationfromsector14andreturnsthattotheapplication,theinformationfromtherestofthetrackisdiscarded.SoRAMisthequickestwayoforganizinginformationforretrieval.WhynothaveeverythingonyourcomputerstoredonRAM?Theansweriscostandvolatility-RAMcostsfarmoreperGBthanaharddriveandmostRAMrequirespowertomaintaintheinformationstoredinit(It'smemoryis"volatile").IfyouhadaRAMonlycomputeryouwouldhavetoreloadtheoperatingsystemandallyourapplicationsanddataeverytimeyouswitchedoffortherewasapowercut.Thereareappropriateusesforthistypeofcomputer(e.g.thinclients)butgenerallyasystemisbestservedbyamixofRAMandDrivestorage.YourcomputerneedsdifferentamountsofRAMfordifferenttasksandthemoreapplicationsyouopenthemoreRAMisrequired.YoumightthinkthatsoonerorlateryouwillrunoutofRAMandthenwhat?Welltheoperatingsystemisdesignedtocopewiththatsituationby'paging'blocksofRAMtotheHardDrive.WhatthatmeansisifthesystemisrunningoutofRAMittakesthecontentsofa'chunk'ofRAM(usuallytheleastusedpart)andwritesittoareservedareaoftheHardDrive,calledthePageFileorSwapSpace.The'chunk'ofRAMisthendeclaredfreeforuse.ByusingtheswapspaceinthiswaythesystemnormallyneverrunsoutofRAM.ButaswehavealreadydiscussedaccessinginformationontheHardDriveisinherentlyslowerthanaccessingitfromRAMsotheresultisthecomputerslowsdown.Noonelikesaslowcomputersowhatdoyoudoaboutit?ObviouslyyouwanttoaddmoreRAMbuttodothisyouneedtomatchtheadditionalRAMwithwhatisalreadyinyourPCandyouneedtobesureyourmotherboardwillsupportthekindofRAMyouintendtouse.

DifferentTypesofMemory&SomeTerminology

In"thebeginning"RAMcameintheformofsemiconductorchipswhichwereindividuallyplugged,orsoldered,intothemotherboard.Thatmadeuptheoriginal640KBofsystemmemorythatDOShungontoforsolong.Nowmemorycomesinclip-inmodules,usuallycalledmemorysticks(nottobeconfusedwithUSBFlashdriveswhichsometimesgobythatname).Memorysticksormoduleshavechangedformatovertheyearsastheircapacityhasincreased.Hereisalistofthemaintypes,inroughorderofincreasingcomplexity,alongwithothertermsusedtodescribethem:

A 30pin SIP module

A 30pin SIMM module

A DIMM module *

A DDR module with heatspreaders *

A DDR2 module with large heatspreaders *

§ Pins-Originallythenameforthe"legs"onamemorymodule,similartothelegs(orlead)onanelectronicchip.Theterminologyhascarriedovertodescribethenumberofcontactsonmemorymodulesevenwhentheyarenotpins.

§ Bus-Agroupofelectricalconductorslinkingdifferentpartsofthecomputer.Justasabusinreallifeisameansoftransportinglargenumbersofpeoplefromonelocationtoanother,soabusinacomputerisameansoftransportinglargenumbersofsignals(ordata)fromoneintegratedcircuittoanother.Forexamplethefront-sidebus(FSB)transportsdatabetweentheCPUandtheMemoryController(andtootherdestinations).Busesmaycontainsubgroupsthatarealsobuses,forexamplethe"MemoryBus"whichlinkstheMemoryControllerandtheRAMcontainsanaddressbus,adatabusandacommandbus.

§ SIP-SingleInlinePackage-anobsoletetypeofmemorymodulewithasinglerowof(actual)pinsalongoneside.

§ SIMM-SingleInlineMemoryModule-anobsoletetypeofmemorystickwithpoweranddatacontactsononesideoftheboard.30pins.

§ DRAM-DynamicRandomAccessMemory-agenerictermdescribingRAMinwhichthedataneedstoberefreshedcontinually.VerywidelyusedinmassproductionPCs.

§ SRAM-StaticRandomAccessMemory-agenerictermdescribingRAMinwhichthedataisretainedwithouttheneedtorefresh.Faster,largerandmoreexpensivethanDRAM.

§ CacheMemory-Cacheisatermusedtodescribeanumberofdifferentfunctionsinthecomputer.CachememoryisaseparatestoreofSRAMusedbytheCPUtostorethemostfrequentlyused'information'.ThecachecanbeaccessedmorequicklythannormalRAMsobystoringfrequentlyusedfunctions/datathereanoverallspeedincreasecanbeobtained.Therearedifferent"levels"ofcachedependingonhowclosetheyaretotheCPU,Level1cacheisactuallypartoftheCPUchipitself,Level2andLevel3areexternaltotheCPUusuallyonthemotherboard.

§ FP-FastPageRAM-AtypeofDRAM,introducedin1987,whichallowsmultipleaccessestoamemorylocationwithouttheneedtore-specifytheaddress.

§ EDO-ExtendedDataOutputRAM-atypeofDRAMwhichusesassumptionsaboutthenextmemoryaccesstopre-readdata.Introducedin1990withapprox10%increaseinspeedoverFastPage.SometimesknownasHyperPageMode(HPM).

§ DIMM-DualInlineMemoryModule-amemorystickwithpoweranddatacontactsonbothsidesoftheboard.

§ Parity-ParityispartofanerrorcheckingprocessthatcanbeusedtoverifytheintegrityofdatastoredinRAM.Thedataisstored,asisalwaysthecaseincomputers,inbinary-asequenceofeightonesandzeroeswhichmakeupthebyteofdata.TheParityofthatdatabyteisfoundbydeterminingwhetherthereareanoddnumberorevennumberofonesinthedata.Theparityofeachdatabytecanthenbestoredbyaddinganadditionalbitofdata,whichcanbeeitheraoneorazero.Thisextrabitofdataiscalledthe'ParityBit'.Inthe'evenparity'systemifthetotalnumberofonesinthebyteisanoddnumbertheparitybitissettoone,thuseveningupthenumberofones.(Thereisalsoan'oddparity'systemwhichistheotherwayroundjusttoconfuseusall).Whenthedataisreadbackintothesystemthecomputeragaincalculatestheparityofthedatabyteandcomparesthattotheparitybitthatwasstoredwithit.Ifthecalculatedandstoredparitiesagreethenalliswell(usually)butiftheydisagreethentherehasbeenanerrorandthedatabyteissuspect.TouseparityerrorcheckingtheRAMmustbeabletostoreninebitsperbyteofinformation.

§ ECC-ErrorCorrectingCode-RAMthathasadditionaldatastorageforchecksumbitstoallowcorrectionoferrors'onthefly'.Thememorycontrolleronthemotherboardmustsupportthisfunction.

§ SDRAM-Singledata-rateSynchronousDynamicRandomAccessMemory-Introducedin1997,memoryaccessissynchronisedtothebusclockandthebusis64bitswide.168pinmodules.

§ RAMBUS-ArevolutionarymemorytechnologydevelopedbyRambusInc.basedonatypeofvideomemoryanddesignedforuseinPCswithIntelprocessors.Introducedin1999.

§ RIMM-RambusInlineMemoryModule-thememorystickusedinsystemsusingRambusRAM.184pinmodules.

§ C-RIMM-ThecontinuitymodulerequiredtofillemptymemoryslotsintheRambussystem.

§ RDRAM-RambusDRAM-originallydesignedtooperateatbusspeedsofupto800MHzbutonly16bitsinwidth.

§ DDR-DoubleDataRatememory-atypeofDRAMbasedonSDRAMtechnologythatoperatesattwicethebusclockrate.Ituses184pinmodules.Releasedin2000.Thiswasthemainstreammemorytechnologytotheendof2005.

§ SODIMMandSORIMM-SmallOutlineversionsofDIMMandRIMMsticks.Thesearesmallerandthinnermemorymodules,typicallyusedinlaptops.Moduleshave144or200pins.

§ SPD-SerialPresenceDetect-circuitry(anEEPROM)builtintoaRAMmodulewhichwillsendinformationtotheBIOSandtotheMemoryControllertoinformitwhattypeandhowmuchmemoryispresent,whereitisandsetupcomplextimingparameters.

§ HeatSpreader-Athinmetalcovermakingthermalcontactwiththememorychipsandassistingincooling.Alsoallowsmanufacturerstoputlargelogosandbadgesonthememorymodules.

§ DDR2-DoubleDataRate2memory-atypeofDRAMbasedonDDRtechnologythatoperatesattwicetheclockrate.Releasedin2004.Thisisexpectedtobethemainstreammemorytechnologytotheendof2007.NotcompatiblewithDDRmotherboards.Moduleshave240pins.

§ DualChannelMemory-ThereisnodifferencebetweenDualChannelDDRMemoryandordinaryDDRMemory,it'sthemotherboardthatisdifferent.SystemsthathavedualchannelcapabilitiescaneffectivelydoublethebandwidthoftheMemoryBusbyaccessingtheRAMmodulesinpairs.TouseDualChannellingyouwouldpurchaseRAMinmatchedpairsandinstallitsymmetricallyacrossthememorychannels.

§ VirtualMemory-ThisisRAMthatissimulatedbythesystemwhenrunningoutofspaceintherealmemorymodules,itisactuallyspaceontheHardDriveandassuchisfarslowertoaccessthanrealRAM.Significantdegradationofsystemperformanceoccursifmorethanacertainpercentageofcurrentdataresidesinvirtualmemory.

§ Latency-Adelayinterval.IwashopingtoglossoverthisbutsomanyRAMcompaniesquotelatencyfiguresit'sboundtocomeup.SeethesectiononLatencybelow.

§ Bank-Agroupofmemorychips(notmodules)thattogethercansupplyenoughdatabitstoequaltheCPUdatabus.Inthedaysof30pinmodulesmemorychipsonlyheldonebitperaddressandyoucouldonlyfit8chipsonamodulesoto"fill"the486CPU'sdatabus(whichwas32bitswide),youneededfourmodulestomakeonebank.Theintroductionof72pinSIMMsmeantthewhole32bitsofdatacouldbesuppliedbyonemodule,butwhenthePentiumCPUwasintroducedwitha64bitdatabussoyouneeded2SIMMstomakeabank.ThisexplainswhyownersofolderPentiumsystemsalwayshadtoaddorupgradetheirmemoryinpairs.Withtheintroductionofthe168pinDIMMthisdrawbackwasovercomeandnowtherecanbemanybanksofRAMononememorymodule.

§ Rank-rowofmemorychips.Usuallyarankfillsonesideofamemorymodulesoifyourmodulehastworanksthatmeanstherearechipsonbothsides.

CommonRAMSizesIfIremembercorrectlytheoriginalSIMMscamein256KB,512KBand1MBpackagesandcostasmallfortune.InthedaysofWindows95acomputerwouldcommonlyhaveseveral4MBor8MBmemorymodules.BythetimeWindows98cameoutthesehadbecome16MBor32MBmodulestomakeuparound64MBinagoodsystem.ForWindowsXPcomputers128MBisaworkableminimumdependingonwhatapplicationsyouwanttorun,modulestendtobe128MB,256MBor512MB.Currentlysystemsroutinelyshipwith512MBsticksand1GBsticksarebecomingmorecommon.

RAMmodulesizesalwaysdouble:4MB,8MB,16MB,32MB,64MB,128MB,256MB,512MB,1GB,2GB,etc.(sincestrictlyspeaking1GB=1024MB)Youwontfindany96MBRAMmodulesforexample,butyoursystemmayhavean"unusual"amountoftotalRAMforacoupleofreasons

§ ThesystemcontainsdifferentsizedRAMmodules.§ Forexampleyoursystemshows192MBofRAM.Mostlikelythiswas

asystemthatstartedlifewith64MBofSDRAMandwasupgradedbyaddinga128MBmodule.

§ Thesystemhasonboardvideo.§ Whenasystemhasonboardvideothevideo'card'isintegratedinto

themotherboard,butnovideomemoryisprovided,insteadthesystemreservespartofthesystemRAMtoactasvideomemory.HowmuchmemoryisreserveddependsonsettingsintheBIOSandisusuallyanystandardsizefrom4MBto64MB.The'total'amountofRAMthatWindowsseesisthenthesizeoftheRAMmodule,lesstheamountreservedforvideo.Thiscanresultinsomeveryodd-lookingamountsfortotalsystemRAM.Forexampleasystem'stotalRAMmaybereportedas352MB.Thiscouldbemadeupofone128MBmoduleplusone256MBmoduleless32MBreservedforvideo.

RAMSpeedTheRAMinIntelbasedcomputersisaccessedbytheCPUviathefront-sidebus(FSB)andthememorybus.ImprovementsintechnologyhavechangedthespeedoftheFSBdramatically.SimilarlytheRAMitselfhasamaximumspeedatwhichitcan

reliablyoperateandthismustbeatleastashighasthememorybusspeed.Clearlythereisa'greyarea'wherethedefinitionofreliableoperationismadeandthisisonedifferencebetween'lowquality'and'highquality'RAM-thehighqualityRAMislikelytooperatewithcloseto100%reliabilitysignificantlyabovethebusspeedforwhichitisrated.Thisisoneoftheregionsthatover-clockersexploittoboosttheirsystemperformance-increasingtheFSBspeedtotakeadvantageoftheperformance'bufferzone'ofgoodqualityRAM.

ObsoleteSIMMmodules(EDOorFP)wereratedbytheresponseofthechipsonthemodulee.g.70nanosecond.OlderSDRAMstickswereratedas66MHz,100MHz(PC100)or133MHz(PC133)speeds.OriginalDDRwasratedatPC1600orPC2100.CurrentDDRisratedasPC3200.OriginalRIMMmoduleswerePC600,PC700andPC800speeds.CurrentRIMMmodulesareratedPC1066.OriginalDDR2isdesignedfor400MHz,533MHzand667MHzspeeds.LatestDDR2isdesignedfor800MHzoperatingspeed.Whatdoesthismeanintermsofquantityofdatathatcouldbetransferredpersecond?Takinginformationfromavarietyofmemorymanufacturerssiteswecanmakeatabletoshowsomecomparisonsofpeakmemoryperformance:

MemoryLatencyNowwearegettingtechnical...InthesimplesttermsLatencyisdelay.Inacomputeritistheinevitablepausebetweenaskingforsomedataandhavingthatdataavailabletobeused.TogiveareallifeexampleIlookedattheNeweggsiteandfoundacoupleofpairsof1GBDDRPC3200RAMmoduleswhichwouldlookniceinmysystem,butamIbetterofforderingtheOCZGoldRAMwith2-3-3-8timingortheMushkinHigh-PerformanceRAMwith2-3-2-6timing?Whattheheckdothosenumbersmeananyway?I'lltrytoofferasimpleexplanation,butifallthisterminologyreallymakesyoureyesglazeoverthenjustrememberifallelseisequalthenthelowerthenumbersare,thebettertheRAMwillperform.Thenskiptothenextsection.Fortherestofusheregoes:

Dataisstoredinyourcomputer'smemorychipsinasimilarwaytostoringdatainaspreadsheet-itisorganizedinrowsandcolumnsandissequentialalongarow.Forexampleina16Mbitchiptherewouldbe4,194,304addresslocationsor"cells"arrangedin2048rowsand2048columns.Eachcellinthechipholdsfourbitsofdata.Partofthechipmightlooklikethis:

Keepinmindtheonesandzeroesarerepresentedbyvoltagelevelsintheformofelectricalchargeinacapacitorintherealchipandthatthesearebeingrefreshedrepeatedly.Toreadthedatainaparticularcellinour2048x2048chipthecomputerneedstoindicatewhichRowthedataisinandthenindicatetheColumnthatholdsthecellcontainingtherequireddata.Itdoesthisbyissuing(inbinary)an"address"fortheRowandthentheColumnusingthesame11bitaddressbusineachcase(becauseittakes11bitstocountupto2048inbinary).ForexampletoreadthedatainthegreencellinthediagramthecomputermustfirstaddressRow3(highlightedinyellow)andafterthataddressisfixeditaddressesColumn2(highlightedinblue).Canyouseeadelayherealready?

Becauseeverythingistakingplaceatmind-bogglingspeedtherehastobea'pause'betweenissuingtheRowaddressandissuingtheColumnaddresstoallowthe

voltagestostabilize.IfthepauseisnotlongenoughtheColumnaddresscouldbecorruptedbyvoltageremainingfromtheRowaddressresultinginthewrongdatabeingread.BoththeRowaddressandtheColumnaddressare"latched"intothememorychipbysignalscalled"strobes",sowehaveaRowAddressStrobe(RAS)andaColumnAddressStrobe(CAS).ThenecessarydelaybetweenthemiscalledtheRAS-CASdelayorTRCD.Allthedelaysreferredtoaremeasuredinclockcyclesratherthanactualtimeintervals.

Oncethecelldata(1010)hasbeenreadthenextfourbitsofdatarequiredare(usually)inthesameRowbutinthenextColumnalongsoonlytheColumnaddressneedstobechanged.Againtheremustbeadelaywhilethepreviousaddress'evaporates'andthenewaddressvoltagesstabilizebeforetheaddresscanbelatched.ThisdelayiscalledtheCASLatencyorCL.

Similarly,oncealltherequireddatainarowhasbeenreadadifferentrowneedstobeaddressed.SincethecontentsofthecellshavetoberefreshedandthisisdoneonaRowbyRowbasisthereisanotherdelayrequiredcalledtheRASPre-chargetimeorTRP.

Thememoryinyourcomputerisnotactiveallthetimeandduringthe(tiny)intervalsofinactivitycertainpartsofthememoryareshutdowntohelppreventthechipsfromoverheating.Thisintroducesadelaywhentheyneedtobeactivatedagain.Thisiscalledthe"ActivetoPre-charge"delayorTRAS.

Finallythereisanotherdelaythatmustbeallowedfor,whichisthedelaybetweenthecomputerselectingaparticularmemorychip(astherewillbemanychipsmakingupyourRAM)andbeingabletoissueacommandtothatchip.ThisiscalledtheCommandRateandforsomereasonseemstobewithoutanacronym.

SocomingbacktotherealworldandourexamplesfromNeweggcanyouguesswhatthequoted"timing"numbersare?That'sright-theyarethedelaysorlatencieswe'vejustdiscussed.Here'showatypicaltimingspecificationmightlook:

2-3-2-6-1T§ Thefirstnumber(2)isCL,theCASLatency.Thisvaluehasthemost

effectonsystemperformance.Itisusually2,2.5or3forDDRmemory.

§ Thesecondnumber(3)isTRCD,theRAStoCASdelay.NotascriticalasCL,itisusually2,3or4forDDRmemory.

§ § Thethirdnumber(2)isTRP,theRASPre-chargedelay.Thisvaluehas

similareffectstoTRCD.§ § Thefourthnumber(6)isTRAS,theActivetoPre-chargedelay.This

valueaffectsstabilitymorethanperformance.Typicallybetween5and8forDDRmemory.

§ § Thelastfigure(1T)istheCommandRateandisoftenomitted,asitis

almostalways1T.ForslowRAMitwouldbe2T.Strangelysomeover-clockersgetverygoodresultsbydeliberatelysettingtheCommandRateto2TevenwithlowlatencyRAMasitallowsthemmoreflexibilitywhentweakingtheotherlatenciesandbusspeeds.

NotethatthenumbersarevalidonlyfortheratedclockspeedandwillalsobequitedifferentfordifferenttypesofRAM.

Thereallifeexampleswere2-3-3-8and2-3-2-6bothofwhicharegoodforDDRat400MHz,butIcannowseethattheMushkin2-3-2-6RAMmaybemorestableunderheavyloadthantheOCZRAM.SoIcancheckthepricedifferentialandconsiderwhetherthatislikelytobeanimportantfactorformycomputerusage.

TheselatenciesandtimingfigureshavetobeenteredintheBIOSwhentheRAMisinstalled-thereasonyou'veprobablyneverhadtodothisistheyareprogrammedintotheSPDEEPROMontheRAMmoduleandtheBIOSreadsthevaluesautomatically(unlesssettomanual).IfyouhavetwoRAMmoduleswithdifferenttimingfiguresthentheBIOStakesthehighestfigure(slowestsetting)toworkwith.Thetimingfiguresaremanufacturersrecommendationsforsuccessfuloperation,thereisnolawwhichsaysthememorymodulewillnotworkwithdifferenttimingandthisisfertilegroundforover-clockerstoexperiment.TheyswitchtheBIOSmemorysettingstoManualsotheSPDisignoredandinserttheirownfiguresintheBIOS.IamNOTsuggestinganyoneattempttodothis,unlessyouknowexactlywhatyouaredoing.YoucandestroyyourRAMwithinappropriatesettings.

HowtoIdentifyyourRAMToproperlyidentifyyourRAMyouneedtoknowthetotalmemorysizeinMegabytes(MB),howmanymemorymodulesthereare,thetypeofRAMyouhave,itsspeedandideallyitsmanufacturer.Thereareanumberofdifferentwaysyoucanfindsomeorallofthisinformation.

Belowaresomefreeutilitiesthatcanbeusedtodeterminetheamountofmemorycurrentlyinstalledandthetypesofhardwareinstalled:

§ TheWindowsSystemInformationcommand,asshownabove,allowsmetoseehowmuchtotalmemoryIhaveinstalledinmycomputer.

§ SpeedFanallowsmetocheckwhatRAMIhave:LaunchingSpeedFanfromitsdesktopiconrevealsIhaveversion4.27installed.Theprogramtakesafewsecondstogatherinformationthensettlesdownatthe'Readings'screenwhereitshowsyoufanspeedsandcomponenttemperatures.Clickonthe'Info'tabandclickthe'Readinfo'button.Thisgathersinformationanddisplaysitinthe'DIMMinfo'box.Scrollupanddowntoseealltheinformation.AsshownbelowSpeedFantellsmeIhaveonlyoneRAMstick(DIMM#0)anditisDDR,itdoesnotstoreparityinformation,andthetotalsizeis512MB.IfIhadmorethanonesticktherewouldalsobeinformationforDIMM#1,DIMM#2,etc.

Nowlet'shavealookusingEverestHomeEdition:StartEverest,inthe'Menu'columnonthelefthandsideclickon'Motherboard'.TherighthandwindowshouldchangetoshowCPU,CPUID,Motherboard,Memory,SPD,ChipsetandBIOSicons.Clickonthecrypticallynamed'SPD'icon(foranexplanationseetheSPDentryintheprevioussection).Asshownbelowthisrevealsawealthofinformation.Thesingleentryfor'DIMM1'underdevicedescriptionshowsIonlyhaveonememorystick.Thedetailsbelowshowaserialnumber,dateofmanufacture,size(512MB),type(DDRSDRAM),speed(PC3200)andotherinformationincludingtheManufacturer'sname(KingstonTechnologyCompanyInc.)andalinktotheirwebsite.ItincorrectlyreportsIhavefourDIMMslotswheninfactmymotherboardonlyhastwo.NotethatEverestHomeEditionisnolongerunderdevelopmentandsomeoftheinformationmaybeoutofdate.

AdditionalinformationabouttheMemoryControllercanbefoundinthe'Motherboard'windowbyclickingon'Chipset'andhighlighting'NorthBridge'.ThiswillindicateforexamplewhethertheMemoryControllercansupportDualChanneling,whichyouwillneedtoconsiderifyouareupgrading.

Finallylet'scheckoutourRAMusingthefreewareprogramCPU-Z.Ifyoudownloadedthisfromtheaddressinthe"RequiredTools"sectionyouwillhaveazipfilesomewhereinyourcomputer.Extractthezipfiletoadirectorycalled'CPU-Z'orsomenameyoucanremembereasily.That'sallyouneedtodo,thereisnoinstallationprocess.TorunCPU-ZnavigatetotheCPU-Zfolderanddoubleclickthecpuz.exefile.Thiswillruntheprogramandpresentyouwithareportwindowwhichlookslikethis:

We'reinterestedintheRAMatpresentsoclickthe'Memory'tab.HereittellsmeIhave512MBofDDRSDRAMonasinglechannel,runningat133MHz.IttellsmetheratiooftheFSBtotheDRAMclockis3:2whenIwouldhaveexpectedittobe1:1(Ifixedthislater-seeunder"LookintheBIOS"below).Thistabalsotellsmethetimingfiguresare2-2-2-6@133MHz.(Seethe'MemoryLatency'sectionforanexplanationofthesefigures).Nowclickthe'SPD'tab.InformationforSlot#1isdisplayed,apulldownmenuletsyouselectslot#2,slot#3,etc.,whichinmycasesay"Empty".Therestofthedisplaylookslikethis:

HowmuchRAMdoyouneed?

"640Kshouldbeenoughforanybody."-BillGates1981

IronicthatthisquoteshouldcomefromthefounderofMicrosoft-thecompanywhoseWindowsoperatingsystemgoesthroughcomputerresourceslikekidsgothroughbirthdaycake.

OlderoperatingsystemsrequiredalotlessRAMthenmodensystem.Modernoperatingsystems,andtheirhardware,requirequiteabitmoretoproperlyoperate.Asastandard,mostcomputersthesedaysshouldhaveaminimumof4GB(Gigabytes)inordertoproperlyrun.Inmyopinion,though,thesweetspotis8GB,whichshouldallowyoutorunmostapplicationsandgamesinWindows.

Forthosewhoaredoingheavyvideoediting,graphicsdesign,hardcoregaming,orjustliketohavealotofprogramsrunning,youcannotgowrongwith16GB.

Anythingpast16GBmaynotprovidemuchofaspeedbenefitotherthanbeingabletorunmoreprogramsatthesame.

CanyouhavetoomuchRAM?

Inmodernoperatingsystemsandhardware,havingalotoframwon'thurtthesystem,butyoumaynotactuallybenefitfromit.

Forhistoricalpurposes,herearethedetailsforusingtoomuchraninoldersystems.Forthemostpart,nooneshouldbeusingthesesystemsanymore,soitshouldnotmatter.

§ Windows95andWindows98(firstedition)donotrecognisemorethan256MBofRAM-addingmorethanthiscanslowdownyoursystemmarkedly.ThereishoweverafixforthisdetailedinanAumHaarticle-seethereferencessection.Ifyouhavemorethan1GBofRAM(thoughIcan'timaginewhyyouwould)Windowsmaynotstart.SeetheMicrosoftknowledgebasearticlehere:http://support.microsoft.com/?kbid=184447

§ Windows98SEandWindowsMEhavetroublewithmorethan512MBRAM-youmayget"OutofMemory"errorsorothersymptoms.SeetheMicrosoftknowledgebasearticlehere:http://support.microsoft.com/kb/q253912/

§ Windows98SEandWindowsMEwillnotrunwellwithmorethan1GBofRAM.Thismaycause"potentialsysteminstability"accordingtoMicrosoft.

§ SomeversionsoftheAwardBIOSslowdownyoursystemmarkedlywhenmorethan768MBofRAMisinstalled.

RAMExplainedhttps://youtu.be/PVad0c2cljoWhatisRAM:https://youtu.be/NrMmZPg40Ok