What type of RAM do I need?
Earlier types of RAM were rated in ns (nanoseconds), while SDRAM is rated in MHz (megahertz), because its speed is somewhat dependent on your system's bus. Your motherboard's bus rating will determine whether you can use 66MHz, 100MHz, or 133MHz SDRAM. You can use RAM with a higher rating on a slower motherboard, but only if you plan to upgrade your motherboard someday, since the RAM will only run as fast as your motherboard will allow. On the other hand, since the price for 100MHz SDRAM is so low these days, you might as well pick some up simply to take advantage of the resale value.
PC100 is standard issue for Intel processors that conform to a 100 MHz bus. A 100MHz RAM module without PC100 on the label may not run as fast in your system, since it is only required to peak at that speed, and not necessarily sustain it. The same principles apply to 133MHz modules and the PC133 standard.
Don't just pick RAM at random. The simplest way to ensure you get the right kind of memory is to visit a memory vendor's Web site, and look for a memory configuration page that will match your system up with the correct memory type. When in doubt, check your motherboard manual or call the manufacturer and ask. If you can't get anyone on the line, give the serial number and model name of your computer to the memory supplier. If you have a generic PC or if you built your own, jot down your motherboard model and serial number, and contact your supplier. Based on that information, the supplier should be able to provide the exact memory type you need (and possibly even help you identify which modules are compatible with your system).
If all else fails, take a stick of your current RAM to a local PC repair shop. (Make sure you ground yourself before removing one of the sticks of RAM!) If you see more than one type of RAM, take one stick of each. Put them in an anti-static bag, and then take them to a local PC repair shop. (If you don't have an anti-static bag, pick one up at the repair shop first, or borrow one from a friend or the IS department at work.) They should be able to help you upgrade or replace it. Some shops can even test your RAM to see if it still works.
How much RAM do I need?
There's no hard and fast rule for deciding how much RAM you need. In general, Windows 98, Me, and 2000 prefer 128MB of memory, while Windows 95 is satisfied with 64MB. If you're nowhere near either of those targets, and you've been noticing a lot of disk activity, then Windows has probably run out of memory and is trying to use your hard drive to compensate. If that's the case, it's time to buy more RAM.
How do you determine just how much RAM you need? Take inventory. Make a list of the minimum RAM requirements of everything you run on your system and be liberal in your estimations. You'll definitely need more than what the vendor recommends if you want your system to run optimally. You can run Windows on 8MB of RAM, but you'll be doing a lot of waiting between mouse clicks. Calculate the total memory required to run all the programs you'll be using at the same time on your system, and then step up that number a bit.
|
Go over the minimum if you can, especially if you're using applications that require a lot of memory. Photoshop, for example, keeps duplicate copies of your files. If you're editing photos that are 20 to 30MB, those files can really add up. Factor in at least twice as much RAM as the size of your largest photo. If you spend a lot of time editing video, you'll definitely want to invest in more RAM.
If you run games on your machine, keep in mind that your PC's main system memory determines how all the gameplay elements fit together: game rules, sound, AI, maps, and networking. While most games will run with 64MB, you'll get better gameplay with 128MB. Games that have very large maps or highly detailed gameworlds can eat up a full 256MB of memory. See this list from Kingston Technology for more OS recommendations for specific types of users.
Before you settle on a number, take your current system into consideration. The maximum amount of RAM you can install is subject to the limitations of your motherboard. Check your computer manual and see how much RAM your system supports. For example, if you own a Pentium system with a TX motherboard, anything more than 64MB is too much. The L2 cache on that particular motherboard only supports that much--any more than that will actually slow your system down.
Your system RAM is divided into banks so that your CPU can read one bank while it writes to another. So, if you're upgrading a system outfitted with DIMM sockets, you'll either add a DIMM that matches what you already have, or replace the existing DIMM with one or more higher-capacity modules. The general rule for SIMMs is that their banks must be filled in even multiples. If you have an older system (a 486 or earlier) with eight SIMM sockets, you'll need to add or replace four identical SIMMs at a time (because there are two banks with four sockets each). DIMMs, on the other hand, can be added one at a time because each socket is a complete bank.
