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RAM - RANDOM ACCESS MEMORY
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Just what does ram do? Ram is often termed 'memory' by computer sales officers and system analysts alike. But it is basically the temporary storage area for all the information your Operating System needs to store. It is sometimes used by system devices like the AGP card in order to store very complex data sets to be used only scant nanoseconds later. There are varying degrees of RAM types. Some of them are in hard disks, CPUs, motherboards, CDROM drives and so on .... They are named: Virtual Ram/Pagefile + Data Cache for harddisks L1 and L2 Cache on CPUs FLASHROM on motherboards and data cache on CDROM Getting the idea yet? There are yet many other devices within a computer system which use some type of short-term storage memory. The reason for this is because the device requires some 'processing area' where it can dump large amounts of information and retrieve it later when it fits into the logical sequence in order to carry out an operation. RAM in general will only be alluded to as SYSTEM RAM which slots into your motherboard in specially designed RAM DIMMs -Dual Input Memory Modules. Real old motherboards have EDO RAM *still used on most Apple Macintosh systems*, just OLD motherboards may have SIMMs for SDRAM and some Intel ones may have RIMMs for RDRAM. But we're going to talk about the most common technology at hand which is DDR RAM: DDR RAM (Double Data Rate Random Access Memory) was an initiative by AMD several years ago to bring about a solution to Intels RDRAM (Intel had this high performance ram for a while before DDR came out). The speed of CPUs had increased tremendously -like it has done for the past years, and the thing that was (and is still) holding things up was the bottleneck of CPU to RAM data transfers. The problem lay in software using the older technology for longer as it takes quite some time to bring out a new product for faster systems (we're talking years here). Double data rate meant that ram was 2x the speed of the former SDRRAM (Single Data Rate Random Access Memory) and thus SIGNIFICANTLY FASTER. Once the chipset makers had gotten sample chipsets from AMD -namely the AMD765- in regard to DDR they could then approach motherboard makers (MSI, ASUS etc) and say they had a DDR solution to be used. This process also took some time as motherboard makers didn't see the need to upgrade in a hurry as there were no APPLICATIONS out which would need such a tremendous speed. BUT NOW THERE ARE!!! DDR 200, 266, 333, 400 proceeded and at the moment 600 has been fully developed for first sales this June 2003. And just in the past few days (May 2003) AMD has released a processor which will run a DDR Ram Frequency of 400 FSB. This means the CPU - a Barton 3200+ - will run at 200 MHz External clock (DDR makes this 400 MHz FSB) for it's entire lifetime. Hence the bottleneck reduces. But WAIT! there's MORE! A bottleneck now still exists between the FSB (RAM/CPU) and the PCI bus. The difference has become so great that oftentimes there will be a PCI divider option in the CPU and RAM section of BIOS to change or reduce the PCI frequency to around 33.33 MHz. ISA (should your motherboard have it) also relies on FSB to function and should be at 7.16MHz. What is the PCI bus? PCI (Peripheral Component Interface) bus is a means to connect a series of devices or components that run at a specific speed to the motherboard and thus the rest of the computer. Devices which use PCI are most commonly NIC (Network Interface Cards) or Sound Cards and Video/Audio Editing cards. And even a vast array of other devices from a TVTuner through to an additional hard drive controller. The PCI slots are white and usually number 3 and more in any modern motherboard. It runs the devices at a constant frequency (or should do) of about 33 MHz. Some devices on this bus will run as low as 26 MHz and up to as high as 42 MHz before failing. This is particularly important to watch out for if you are OVERCLOCKING. Another most important factor just like ISA and PCI buses is the AGP bus speed. This is usually 2x the default PCI bus (33.333 x2 = 66.67 MHz). If the PCI value is increased to 42 MHz (and I strongly urge you to NEVER do this) the AGP video card will be set to run at 84 MHz -that's a huge difference and will most likely damage your video card and/or AGP slot. If overclocking your rig/box/system past an FSB of 166 (which equals 40 MHz *CPU/4*) the PCI bus devices will usually have trouble unless a greater divider is used (CPU/5 or CPU/6). 166 FSB should be using a CPU/5 setting and 200 FSB should use CPU/6. 200 / 6 = 33.33 MHz otherwise running at CPU/4 with 200 FSB would damage your PCI/AGP/ISA components running PCI at 50MHz and AGP at 100 MHz. Insane to EVER do this. You are warned... so DON'T go over the top! As you can see all this bares down to the FSB. Hand in hand with DDR RAM and overclocking goes VDIMM Voltages. Increasing them can increase RAM stability by burning/etching a slightly broader pathway between the circuitry on the ram sticks themselves. DDR of 333 MHz (PC2700) or higher should be running at 2.7 Volts, and definitely no lower than 2.5 (which is currently the default for motherboards) Ram errors have and WILL OCCUR if 2.5 volts is selected (usually a jumper on the motherboard still dictates this voltage) and you have 3 or more sticks of RAM in the DIMM slots. For instance, I am running 1 stick of DDR PC3200 (Corsair XMS edition) at 180 FSB with a voltage of 2.8 Volts. Perfect stability for extended hours of gameplay and benchmarks with 2.8 volts. However, if I decrease the voltage to 2.5 volts, the system will become only slightly unstable. If I insert some low-quality DDR 333 (PC 2700) sticks (more than one) and use 2.5v I will get a LOT of memory errors, if set at 2.8v though I get VERY FEW. There's a tip for you. RAM TIMINGS - are what? RAM timings or in the bios called DRAM settings -are values which determine some of the speeds and delays of the RAM and data throughput functions and sizes. A series of settings make up RAM values and it is best you fiddle with each one by themselves to figure out which combination of the several options gives you the BEST PERFORMANCE and/or STABILITY. Lower settings are generally faster (in a 2, 2, 6, 2 combination) and this all depends upon the other components in the system, namely the CPU/RAM stick/motherboard and voltages of all these components and sometimes .. even the PSU! (Power Supply Unit -usually on a Pentium 4 system) I recommend at this moment you go and visit www.amdmb.com and pick the forum relating to your motherboard for hints, tips and tweaks which will help you on your merry overclocking way.. Sorry Intel lovers -this is an AMD only site. Now for those of you who enjoy overclocking and/or do it on a regular basis, may I suggest you have a read of THIS PAGE which details benchmarking and should lead you to what I call 'responsible benchmarking' ... hahahha -responsible ... And in order to REALLY TEST that stability you think you've gotten to try this kewl program AND KEWL INFO SITE!! |