Resolved Compatible RAM upgrades

My Lenovo ThinkPad is 2 years old, so I'm getting an itch to upgrade. It is the system in my profile. I currently have 2x4gb sticks; I have 2 slots that can each take 8 gigs, for a total of 16.

Since the site I want to buy from (crucial.com) has a couple of different options, priced about the same per gig, for 1 8-gig stick, as for 2 8-gig sticks, I'm thinking of just upgrading from my current 8, to 12 gigs--buying only one 8-gig stick right now.

I would just like to make sure that if I do this, the single 8-gig stick that I get now, will be compatible with the current one that I keep, after inserting the 8-gig stick.

Here are the 8 gig offerings from Crucial:
http://www.crucial.com/ProductDispl...anId=AD1BBFC631D926C3&langId=-1&storeId=10151

Crucial 8GB DDR3L-1866 SODIMM CT6223653 | ThinkPad E555 | Crucial.com



My questions:
(1) Can I mix and match either of those 8 gig sticks that crucial has offered me, with my current setup?
(2) My system will still take advantage of all 12 gigs, if I do this, won't it?
(3) Its hard for me to imagine that my system will see the difference between the 1600 and the 1866 speeds, so I'm thinking I should just save a few bucks and buy the 1600 (the first link), for 7 dollars less. Is this correct?

Something tells me that these are questions I should already know the answer to---but I only do RAM upgrades every 4-5 years or so, so I figured I'd be better off asking. Appreciate your patience with me.

 

(1) "In theory", yes. You can mix and match. I say in theory because on-paper and real world don't always jive. The good news is if you buy from Crucial, they guarantee compatibility.

(2) Yes. You have 64-bit Windows so no problem - assuming (1) holds true.

(3) It is important to note that more RAM trumps faster RAM every time. So you are correct to assume you will not notice any difference (except, maybe, on a benchtest report).

Having said all that, it is typically better to use matched sticks of RAM. For one, the chances of compatibility issues between sticks are almost completely eliminated. And for another, most motherboards support dual channel memory architecture. This is a features that allows the CPU to address RAM on both sides of the cycle. While it does not double RAM performance, it does improve it - but ONLY when the two sticks are identical - in other words, only if you install 2 x 8GB. If you mix sizes and run with 1 x 4GB and 1 x 8GB the board only runs in single channel mode (at least for that extra 4G). But now I must refer you back to (3) and will point out that 12GB slower RAM will yield better performance than 8GB of faster RAM.

Now saying all that one more time, it should be noted that for most users 8GB is considered the sweet spot. That is, less than 8GB and performance is degraded. But more than 8GB and performance gains are (again, for most users) marginal, if noticeable at all. If you look at the Performance tab of Task Manager and never approach 8GB of in use RAM, you likely will not notice any performance gains. And in that case, moving to a SSD may be a better use of your upgrade money.

 

Some interesting thoughts, as usual, Bill.

I already have an SSD.

I usually have a few gigs of RAM free, but then again, my browser (FF) now has the capability of using a lot more RAM, if I increase the content process limit (from the default 4), which I'd like to do. In the past, increasing it above default also increased the amount of RAM that was taken up, triggering browser slowdowns or freezes.

Well you gave me some food for thought.

 

Yeah, browsers, especially FF and most especially Chrome can eat up RAM resources. You might consider Pale Moon. It is forked from Firewall and seems to be lighter on resources.

 

I have noticed (and even timed on an empty cache, to be sure) the newest Firefox ("Quantum") to be faster than PM and other browsers, so I'll stick with this. I'd rather pay more for RAM that will be used, and enjoy the speed.

 

Interesting. In the past, when I've used FF and used a high number of content processes, the RAM useage has gone up, and the browser became sluggish. A few days ago, I upped the content process number in FF from 4 (default) to 7 (the max, in the Developer Edition), and RAM useage has increased, but the browser has not become sluggish at all--so it is using the RAM, but not slowing down.

The most FF RAM I've seen used was 1.2 gb; the least amount of RAM I've had available has been 2.8 gigs.

Given what Bill said above--I have 8 gigs of RAM, and its not all being used---I'm not sure I would notice an increase from 8 gigs to 12, so I'll just stay put now, unless something in the above math changes.

 

Sounds like a plan.