The key to computer performance is having enough RAM memory. RAM doesn’t speed a machine up, however. Rather, adding RAM removes a barrier to speed. It’s like your car – taking your foot off the brake doesn’t speed it up, but it stops slowing it down. For starters, you need enough RAM to comfortably boot your operating system and start-up processes. For Windows XP, that could be a minimum of 1 GB, for Vista, Win 7 and Mac OSX, choose 2 GB. However, 4 GB is a more comfortable minimum for modern operating systems.
What won’t more RAM do?
Booting? more RAM won’t improve boot times
Launching of applications? more RAM will give no particular improvement *(note)
Why? The operations above are mostly limited by the read speed of the hard drive, not RAM Notice how you hear the hard drive chunking away continuously when you boot or launch an app? As long as you have adequate RAM for the OS and start-up processes to boot, more RAM is not going to get the files loaded any faster.
What more RAM will do for you is to save the machine from having to hit the Swap files (virtual memory file) as often, and this will remove a significant barrier to performance.
When you open more programs and data than your machine has installed RAM enough to hold, then the operating system is forced to write some of the data in the memory space to the hard drive to make room – called swapping. Then when that data is needed again, it has to write something else to the HD, and read back in the swapped out data.
Because a hard drive is many, many times slower than RAM, this slows the whole machine down while it waits for the data to be swapped in and out.
So, if you only ever use one small program, and you have an adequate amount of RAM, then more RAM will likely not change a thing (because you were never overflowing the available RAM to start with.) But if you do a lot of multitasking, or open programs with a large amount of data, or switch frequently from one program to another, then more RAM should make a noticeable difference in speed (by eliminating some or all of the swapping)
Keep in mind that adding RAM raises the bar, but doesn’t eliminate it. If you load up on many multitasked programs at once, you can push your memory requirements above your new RAM amount. Once you break that level, you can get Swap file slowdowns again. The cure is simple, quit some programs that you aren’t using.
Where more RAM really helps:
Some programs, like Photoshop, graphic production, digital audio, digital video production, large databases, scientific and engineering programs can take advantage of massive amounts of extra RAM to cache data internally, and these programs will run faster as a result, especially with large data sets. The benefit is similar if you have to do a lot of multitasking of large programs. Make sure that you are running a 64-bit operating system and a 64-bit version of the software to take advantage of large RAM installations.
* However, if you have a lot of startup items, or if you already have programs open and you are opening more, then there could be some speedup in booting or launching, simply because your machine is already hitting the RAM limit and starting to page data to the swap file.