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This is the one area of computer building that still has me in the dark, and I think a lot of people are with me...

There are many different types of RAM, with each company having high and low end sticks. What is the difference between the high and low end?

Also, what do the numbers in the latency mean? What is the speed rating (I know 1600 MHz is about normal) and how much is too much? What's the difference between dual channel and single channel? Can you overclock/overvolt? Is there even a point to do so if this was possible?

As you can see, I'm thoroughly confused here. I tried doing some research, but I can't find this information anywhere on the internet. I'm not actually buying RAM, I'm just trying to get a better picture as to how all this works so I can be more educated on the hardware in computers.

Thanks for all the help guys. A wiki may even be better here, I'm not sure.


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This is a good question IMO –  Nifle Aug 9 '12 at 7:44
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Yup, this is the kind of shopping question we absolutely encourage. –  slhck Aug 9 '12 at 8:32
    
This wasn't meant to be a shopping question. I just didn't understand all the parts of ram, so I asked it in this way. If it would help I can edit the question to be less 'buyer oriented' –  nathpilland Aug 9 '12 at 15:30
    
Here's a helpful overview of RAM: technibble.com/types-of-ram-how-to-identify-and-their-specifications –  Griffin Jun 29 '13 at 4:25
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2 Answers

up vote 16 down vote accepted

Each stick may have the same speed, but their specifications differ. It's those specifications that make up for a difference in price. To get a different stick you'll need a different way to produce it; as to increase the amount of memory, get rid of the latency and more. It's the difference in the required resources that makes up for the different price, as well as funding the research behind it and all that.

We already have two other questions that answer some of the confusion:

As for speed rating, that's somewhat subjective so I think the best bet is to look at some current systems and what they have. This will quickly show you what the current speeds are at and what would be considered too much or not enough.

I haven't seen memory overclocking other than changing some latency related settings in the BIOS, which I've never found necessary to do so. Memory overvolting might be possible to provide more stability as you change the latency settings, but unless you do very memory intensive jobs it is most likely not worth it.

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Very thorough answer. Thank you for the research put into this. It definitely clears some things up for me!! –  nathpilland Aug 8 '12 at 21:03
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You will also have to look to the RAS-CAS latencies. These will be different between those sticks. It's something you can consider depending on what you are building. The lower, the better and the more expensive.

RAM is organized into rows and columns, and is accessed by electrical signals called strobes, which are sent along rows to the columns; when data is needed, the CPU activates the RAS (Row Access Strobe) line to specify the row where data is to be found (high bits), then, after a short time, the CAS, or Column Access Strobe, to specify the column (low bits). After that, the data goes to the output line and to its destination on the next clock tick. In other words, the Column Address Strobe dictates how many clocks the memory waits before sending data on. All registers should be full, or errors will result, which means a longer wait to make sure, and slower operation. The shorter the cycle length, the faster the machine runs, at the expense of stability and data.

RAS CAS

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So, let's say we use the memory in my example, the Dominator should (in theory) have the lowest latency and the XMS3 should have the highest? –  nathpilland Aug 8 '12 at 21:02
    
Yes indeed, there might be other factors as well, like additional heatspreaders. –  Lucas Kauffman Aug 8 '12 at 22:25
    
Does RAM ever get hot enough for heat to be a problem? I've never seen RAM go bad because of overheating. –  nathpilland Aug 8 '12 at 22:28
    
Well, some RAM is aimed at overclockers, overclocking a cpu also means increasing the voltage of the memory, generating more heat. –  Lucas Kauffman Aug 8 '12 at 22:29
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There are special heat spreaders as well in the aftermarket, even fans that fit on top of the memory. –  Lucas Kauffman Aug 8 '12 at 22:36
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