The speed of the ram or it's stable overclock makes a little larger difference IMHO.
I think there is balance that needs to be obtained. Faster RAM is not really going to help if you don't have enough RAM to begin with. I would much rather have 6Gb of standard speed RAM than 3Gb of super fast RAM, for example. And if I am bottlenecking performance with a graphics card that can't keep up, then extra and/or faster RAM will just be in a "hurry up and wait" state most of the time - a waste.
Some people will say that 4GB with Win 7 Ultimate is very adequate, but it will utilize more if it is avaiable. Go with matching modules or a matched kit of 12GB.
4Gb is more
than "adequate" for most
people! In fact, so is 3Gb on a triple channel architecture motherboard.
Most people use their computers to research on the Internet, do work and school (Office) projects, read email, manage their photos, and music, do their banking and social networking, and perhaps watch an occasional movie.
Most people don't do hard-core gaming or graphics editing. And by graphics editing - that's not photoshop stuff - that's serious computer aided design and engineering (CAD/CAE) graphics.
Sadly, we don't know the intended purpose here.
That said, "adequate" in my book means "satisfactory - just barely
". That would probably be running with 2Gb or less. With Windows 7, my recommended minimums
are 3Gb or 4Gb (depending on channel architecture) for more than
"adequate" performance for most
people, even the occasional gamer.
As Britton notes, Windows will happily use more if it is available. And to that, my preferred and the "sweet-spot" (that is, the most bang for your money) with Windows 7 and modern hardware is 6Gb for triple channel and 8Gb for dual channel motherboards. Less than that and performance degrades at a steep, noticeable rate; more than that and performance gains are just marginal, if noticeable at all. And much of that is because 6/8 is already more than enough.
Of course, to take full advantage of 6, 8 or more, you MUST have a 64-bit OS. But 32-bit is legacy stuff. Windows 7 and 64-bit are meant for each other.
6Gb is already a lot. Will you notice an improvement bumping to 12Gb? I know I would be upset if I didn't. But the facts are, it may not be noticeable at all. And if it is, it would only be during "extreme" demands - which tend to be few and far between. What does Resource Monitor say now? My motherboard is dual-channel, so I have 8Gb. I rarely have less than 5Gb available. Though not a gamer, I do have two 22" widescreens full of gadgets (and they can use a lot!
), open docs and browser windows with many tabs, Mailwasher, and Sirius/XM Internet radio streaming - currently using 2605Mb total. So the question is, do you need more than your 6Gb or would your money be better spent somewhere else?
We also don't know anything about the rest of your system. Can your PSU and system cooling handle the extra demands? What is your graphics solution?
At this point, not knowing anything else about your system, my recommendation would be my standard recommendation when there's already a decent amount of RAM - spend your money on more graphics horsepower instead of RAM - even if that requires a power supply with more horsepower too.
Today's computing is VERY graphics oriented. If you already have a monster graphics card (or two) (or three!), and a properly sized, quality PSU, and money to burn - then go for the RAM. Wait! Which i7?