All About RAM (Memory) Upgrades

Wizcrafts Computer Services

About Computer RAM | RAM Upgrades

The history and development of computer RAM, and considerations when upgrading your computer's memory.

By Wiz Feinberg

Definition of computer RAM:

RAM - an acronym for Random Access Memory - A type of memory chip that can be written, read, and re-written to and from, in any random order, while it, or the computer in which it resides is powered on. You can read and write to any part of it, thus the "random access" in the term. The term "RAM" refers to a computer's main memory, or the physical RAM modules installed in the system, and is usually measured in megabytes (mb), or recently in gigabytes (gb). (1,024 Bytes = 1 Kilobyte (KB); 1,024 Kilobytes (KB) = 1 Megabyte (MB); 1,024 Megabytes (MB) = 1 Gigabyte (GB))

A short history of RAM development

Early types of computer storage varied from vacuum tubes to magnet-cores with coils of wire wrapped around them. These were eventually replaced by transistors, and in 1970, by discreet modules known as integrated circuits (ICs), which contain a large number of tiny transistors, capacitors and other components. It was 1970 when the newly formed Intel company publicly released the 1103, the first DRAM (Dynamic Random Access Memory) chip, in the form of an IC. Modern RAM now comes in the form of long PC board wafers, with banks of integrated circuits on one or both sides of the wafer. You can read more about the early developers of integrated RAM modules here.

When I got my first Windows computer, in 1994, it had a motherboard that supported a 66Mhz CPU and a total of 16 mb of RAM. There were four - 4 mb, 33 pin, 70 nanosecond (access time) chips, known as SIMMs, in the four slots. These chips ran on motherboards that had a clock speed of 33 or 66Mhz. A short time later, around 1995, the motherboard manufacturers began adding support for 72 pin, 16 mb, 50 nanosecond EDO RAM modules that were being built, for a grand total of 64 mb in four 72 pin slots. That persisted until around 1996, when 168 pin SDRAM (Synchronous Dynamic Random Access Memory), and motherboard support was created, with capacities of 64 mb per module, and access times of 10 nanoseconds, or faster. These first generation 168 pin modules, called DIMMs, ran at higher clock speeds of 100Mhz, almost double the previous technology.

Single Data Rate SDRAM persisted as the mainstream memory product throughout 2001, with motherboards supporting slightly higher, stable clock speeds of 133Mhz, and the emergence of 266Mhz Bus speeds. As the maximum usable speed of CPUs increased, taking advantage of higher clock rates, the speed of the RAM became a limiting factor and was the cause of data bottlenecks. The RAM manufacturers went back to their desks and designed a new type of RAM that operated on both the rising and falling edges of the system clock wave, and named it DDR, for Double Data Rate. Most DDR has 184 pins. This type of RAM processes data twice as fast, per megabyte, as Single Data Rate RAM. Since 2002 there has been an explosion in CPU, memory and motherboard technology that has sprouted a new crop of DDR, Dual Channel DDR and Rambus memory chips exceeding 2 gb (2000 mb) each, with response times based on twice the system clock and Bus speed (now up to 533Mhz, with some Intel CPUs running at 800Mhz Front Bus Speed), at prices often less than what a 16 mb, 72 pin, 50 nanosecond chip sold for in 1995. This as CPU speeds are approaching 4 Ghz (4000 Mhz). A far cry from my DX-2 66 Mhz CPU from 1994!

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Minimum and maximum RAM requirements for Windows operating systems

Whereas Windows 3.1 and 95 could run on a computer that had 16 mb, and Windows 98 did reasonably well with 64 mb, all of the Windows operating systems from Windows 2000 up require at least 128 mb to operate properly. A typical Windows XP computer sold by almost any major manufacturer will include 256 to 512 mb of Double-Data-Rate Ram (DDR). Most people may not be aware that Windows 98 is capable of addressing up to 1 Gigabyte of RAM, mainly because the motherboards originally built for that operating system didn't have chipsets capable of supporting that much RAM. Motherboards which are built to support Windows XP 32 bit contain chipset support for up to 4 Gb of DDR RAM. Both Windows 2000 and XP 32 bit operating systems can support 4 Gb of RAM, in theory, but in practice many builders have found that the practical limit used by the OS is between 2.5 to 3 GB. The 64 bit version of the Windows XP operating system, with matching 64 bit motherboard hardware and matched RAM, can theoretically address up to 16 terabytes of RAM. In actual use the RAM limit for Windows XP x64 looks like around 128 GB, at this time. See this Microsoft article for a comparison between Windows XP 32 and 64 bit operating systems's usage of RAM and pagefiles.

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What is wrong with running the minimum amount of RAM?

While the minimum recommended amount of RAM will run your computer, it may not do so at the maximum speed attainable. The installed RAM is shared between the operating system, which loads itself into memory at startup, and any background processes (that have been installed with applications), which also launch at startup. If you only have the minimum recommended amount of RAM your computer may begin to slow down, just upon starting up, and your operating system will be forced to swap out code instructions to your hard drive, which is very much slower to respond than RAM chips. In Windows 9x systems this is called the Swapfile, and in Windows 2000 up it is called the Pagefile. In either case, as your computer loads more processes than it's installed RAM can manage, the excess code is sent to the hard drive for temporary storage. When it is needed again the code is swapped back into memory, forcing the last unused instructions in memory to be swapped to the hard drive. As you add and use applications, and more background support processes that run at startup, you may find that you once fast computer is slowing down. If you can't live without the applications that are slowing your computer down you have two basic options (aside from defragmenting) to speed things up: swap out the CPU for a much faster unit (maybe not possible for your motherboard, or possibly quite expensive), or add more RAM.

If your computer seems sluggish when starting up, opening programs, or displaying the contents of new Windows or Start Menu items, or you hear a lot of hard drive activity, you will likely benefit from an increase in your system RAM. Adding RAM is usually the most economical method of increasing your computer's performance, and many people have learned to install new RAM modules themselves. However, finding compatible quality RAM, at the best street prices, can be a real challenge if you buy it from retail stores, and buying cheap RAM anywhere is a crap-shoot; it may or may not be recognized by your motherboard. This is why I buy my RAM online from Crucial Technology. Their RAM is guaranteed to work, with a huge searchable database that matches motherboards to the most compatible RAM, at prices that are always the best on a day to day basis.

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Dual Channel Computer RAM

There is a relatively new development in the way RAM is addressed by the motherboard, which results in much faster performance for any given amount of memory. This technology is known as a Dual Channel Memory, and is addressed by a special, Dual Channel Memory Controller. The Controller splits the data simultaneously between two channels, resulting in twice the data flow that single channel RAM can process. If your motherboard supports Dual Channel Memory it will usually have different colors for the RAM sockets, for the different channels, but identical pin-out connections. In the case of my Asus A7V880 Motherboard, one channel has black and the other has blue sockets, each with 184 contacts, which use matched pairs of PC3200 RAM. When using only two modules you must fill the same socket colors first. If you decide to add another matched pair, they should go into the other pair of different colored sockets. The RAM modules used must be purchased as a guaranteed matched pair, hence they tend to cost a bit more.

When I wanted to order new Dual Channel RAM for my Asus A7V880 motherboard, but could not find any catagory for Dual Channel kits on their website. After chatting online for a couple of minutes I was informed that I only had to order two modules of the identical part number, which I was given, and that they were guaranteed to work in Dual Channel mode. The RAM arrived a few days later and has been running flawlessly, ever since, in Dual Channel Mode, without errors. Crucial has since added guaranteed matched pair kits to it's lineup, for use in dual channel systems.

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Why is only half of my RAM recognized?

This pertains to a situation where upon booting your computer, the system (BIOS, motherboard, memory controller, computer) only sees (counts) half of the physically installed RAM, or less. This usually occurs immediately after one or more RAM modules have been installed.

I must stress here that there can be consequences from adding RAM that is not compatible with your memory controller hardware, or other memory modules. Some memory controllers require a certain speed rating, or maximum chip density, or single-sided modules only, and will not count the full amount of RAM, or may generate unexplainable program errors or fatal exceptions, if you install an incompatible module. This happened to one of my customers a while back, when he ordered a less expensive 512 MB PC133 RAM module, only to discover that his motherboard counted just 256 MB (half). I took 512 MB of Crucial RAM out of one of my PCs and inserted into his computer, and his motherboard saw the full amount of 512 MB. When I plugged his RAM into my motherboard it saw the full 512 MB. This was a case where his motherboard and memory controller didn't like that bargain RAM, but worked just fine when equipped with good quality Crucial RAM, and my system was forgiving enough to recognize his RAM at full capacity.

About Chip Densities:
Early SDRAM chipsets, such as BX, ZX and LX can only support SDRAM density below 16Mx8 (it also supports 16Mx4). The newer 32Mx4 and higher parts often seen in 256MB and 512MB DIMMs are not compatible. They will not work at all, or the computer system will only see half or quarter of the installed DIMM. The important number to look for in memory modules for these motherboards is the x4 or x8 at the end of the density code (16Mx4, 16Mx8, BUT NOT x32 or x64). BIOS updates will not help because the limitation is built into the hardware of the memory controller chipset.

As mentioned in the previous paragraph, I have personally found that Crucial RAM will be recognized at full capacity on older motherboards that only see half the available capacity in lesser quality, off-brand modules! This is especially true for 100Mhz motherboards that need more RAM. Don't waste you money on cheap RAM if you are upgrading an older computer; buy Crucial RAM and do it right the first time! Use the Crucial Memory Advisor below to find guaranteed compatible RAM for your motherboard (and it's memory controller chipset).

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Some other consequences of using mis-matched cheap RAM

Some motherboards from the late 1990's used PC100 DIMMs and may refuse to boot or POST if you insert PC133 RAM. Also, your RAM is only as good as the weakest link, so if you add cheap, off-brand RAM that has input-output errors your computer will have a lot of program crashes and memory address access errors, and may even suffer from unexplainable random shutdowns. That's why I recommend Crucial Memory, to the point of being pushy. If you lookup a memory upgrade for your computer or motherboard, it is guaranteed to be compatible, or you get your money back. You can even chat online with Crucial support staff to find exactly the right RAM upgrade for your motherboard or system brand and model.

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My recommended solutions:

First, before you go and buy more RAM, turn off the power to your computer, open the case, touching bare metal on the case to discharge any static in your body before touching any electronic parts inside. Locate you memory modules, then carefully push down on them to be certain that they are firmly seated in their sockets. Loose sockets can cause memory errors and system crashes and shutdowns. Dirt in the contacts will also cause problems, so get a can of compressed air and blow all dust and dirt out of all the RAM sockets before (re)installing your (new or old) RAM modules. Make sure that the clips on the ends of the sockets are locked into the notches in the ends of the memory modules, and that the RAM is pressed into all of the contacts equally, and any notches in the RAM line up exactly with the alignment keys on the sockets.

Crucial Technology, a division of Micron, makes every type of memory, for PC's, notebooks, digital cameras, PDA's and portable multimedia (MP3) players. Place an order of $40 or more at Crucial.com and get free 5 to 7 business days shipping within the contiguous US. When you buy Crucial memory, you're buying directly from the largest DRAM manufacturer in America and one of the top three in the world. You will get discounted, direct-from-the-manufacturer pricing on high quality RAM, with a money back guarantee. I invite you to use the Crucial Memory tools below to search for memory upgrades for your computer, or other device, by brand, by motherboard, or generically.

TigerDirect carries a dozen brands of RAM in standard, high, game and overclockers' quality, in all pin-out and speed configurations, for all brands of motherboards and computers. Their prices are highly competitive with frequent special price deals.

OCZ Dual Channel Gold GX 2048MB PC4000 Gamer Memory
If you are an overclocker you should checkout the extreme performance capabilities of OCZ 2048MB Dual Channel PC4000 DDR (shown on left), from Tiger Direct.

Specs: Memory Size = 2 x 1024MB; Memory Speed = 500MHz, PC4000; Memory CAS Latency = 3-4-3-8; Memory Type = Dual Channel DDR; Pins = 184

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Crucial Memory Search Tools

How much RAM will help your system?
First you need to find out how much RAM is currently installed in your computer. The three most common ways of finding this out are - #1: watch the very first boot-screen (from a cold boot) carefully to see how much RAM is counted, or, #2: from within Windows, right-click on the "My Computer" icon (or Start Menu link in XP), then select Properties. The amount of installed RAM is displayed on the General Tab, usually as the last item down, under the "Computer" section. Or, #3: Open the case, remove the RAM from it's slots and see what is written on the memory modules regarding their capacities, in Megabytes, and the Bus speed rating or technology used (Fast Page, EDO, PC100, PC133, PC2100, PC2700, PC3200, PC4000, etc). Make a note of how much is installed, then consult the Crucial Memory Advisor Tool, to see how much more RAM you can add to your system.

Apple MacIntosh owners should Use the Crucial Mac Memory Advisor Tool.

If you are still unsure which computer memory upgrade you need, or the maximum you can use, or the required specifications, the Crucial System Scanner, an ActiveX control for Internet Explorer users, reads your total system memory and the make and model of your motherboard, then displays a page with information about your motherboard's maximum memory capacity, and how much you can add, along with all of the compatible RAM modules that are guaranteed to work in it. This really takes the guesswork out of upgrading.

Search Crucial for CompactFlash or other memory modules, and readers, for digital cameras and multimedia devices

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Did you build your own computer and need RAM info?
The Crucial Memory Calculator™ is designed specifically for people who are building their own systems. The Crucial Memory Calculator™ includes information about motherboards rather than information about complete systems. You'll find performance benchmarks for motherboards with various processors, operating systems, and different amounts of memory.

Are you an overclocker needing overclockable RAM?
It doesn't matter how fast a memory module is if it isn't stable and doesn't fit your system. Software crashes, choppy game play, and driver and operating system hiccups — all can be caused by bad memory modules. Performance and stability are Crucial! Don't settle for anything less than Ballistix! Ballistix RAM modules feature attached aluminum heatspreaders, very high stability, overclock-ability, low latency and now, the 256 MB and 512 MB DDR PC3200 Ballistix modules feature solid 2-2-2-6 timings at over 200 Mhz. Check Out Crucial Ballistix Memory and read the kudos from various overclockers' organizations.

Crucial Video Cards
Is your system old and out-of-date? Are you frustrated with choppy graphics or slow game play? Do you experience hiccups during photo or video editing? Or, maybe you're building your own PC and you want to make sure your new system delivers cutting-edge imagery. Crucial has the answer — the Crucial RADEON™ series of graphics cards. Crucial's feature-packed graphics card line-up offers something for everyone — from AGP-based cards offering dramatic improvements for older systems to PCI Express™ cards, the very latest in graphics card technology. Whether you're a PC enthusiast or a hardcore gamer, a new graphics card dramatically improves your computing experience with outstanding visual realism and real-time 3-D performance. Take your system to the next level with a new Radeon video card from Crucial.com. Buy one today!

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