The Novice Computer Upgrade Series: Memory

All of these DDR’s are SDRAM – Synchronous Dynamic Random Access Memory. It is normally used in home/office computers. The actual memory chips are mounted on a circuit board. We call the combination a DIMM (dual in-line memory module). Laptops use SO-DIMM – small outline dual in-line memory module. Pin counts vary between desktop (DIMM) and laptop (SO-DIMM) for the same DDR and speed. So, you have to pay attention to get the right memory. When searching online use the pin count.

Laptop Memory - SO-DIMM

Laptop Memory – SO-DIMM

There is a type off memory that includes ECC (Error Correcting Code) in the discription. These chips know when they forget a bit of data, make a mistake. They alert the system, which usually means a full halt, a controlled crash.

ECC memory is for very specific applications where the physical environment is extreme or the integrity of the results has to be extremely reliable, generally scientific computing. An example would be the Large Hadron Collider, where a mistake would invalidate the research.

ECC memory is almost never used in gaming computers. ECC and non-ECC memory are NOT interchangeable. A motherboard has to be specifically designed to use it. That tends to make them more expensive. You use one of the other with any given motherboard. Your motherboard specs tell you if ECC memory can be used.

The motherboard specs tell which size DIMM’s you can use and the maximum memory the board can handle. A DDR4 stick can come in 1, 2, 4, 8, and 16GB sizes. If the board will handle 4-16GB sticks, you can install 64GB of RAM. My older ASUS P5N32 board has 4 memory slots but, the largest stick it can handle is a 2GB module. So, it is limited to a max of 8GB of RAM.

Memory Performance

For a benchmark of memory performance see: http://www.legitreviews.com/ddr4-memory-scaling-intel-z170-finding-the-best-ddr4-memory-kit-speed_170340/6

For our purposes we can generally assume faster and bigger is better. But, if you are trying to get the best performance for dollar spent, you’ll want to look at the reviews.

AMD & Intel Memory

There are people selling memory which they advertise as for AMD or for Intel. If you are not over-clocking, there is no physical difference. If you read the stickers on the memory sticks, you won’t see a difference, in most cases.

With many electronic components the whole speed thing is sort of misleading. In general all memory chips are manufactured to be the fastest possible. They are then tested to see what speed they will reliably run. Fewer chips run at top speeds, so they charge more for those. But, the slower chip likely came off the same assembly line. It just, didn’t test as well.

When the chips are put on the DIMM package it is tuned for the speed the chips tested at. Which is how the computer knows what speed to run it at.

AMD memory has been tested with AMD CPU’s. Intel memory has been tested with Intel CPU’s. That is about the only difference in AMD vs Intel memory. Of course if you by cheap AMD memory for your Intel machine and want to return it, you’ll likely run into a problem.

Basically, buy the fastest memory your motherboard will support. For my z170 and i5 I went with 2666mhz as performance per dollar plateaus at that point. When I win the Lottery I’ll upgrade. Or if I find good prices on memory at eBay…

Installing

Memory is easy to install or replace. With the case open you’ll easily find the memory sticks. At each end of the stick is a clip (locking arm) when pulled out and down releases the stick and often it pops out.

Putting a memory stick in is a matter of making sure you have notch lined up and pushing it in. It takes some muscle. Most memory sticks snap into place and the clips at the ends pop up.

If you run into a problem, the manuals for most motherboards show how to insert and remove memory. Here is a recent ‘how to’ video by Kingston.

You may have noticed Kingston has a tool for selecting memory. Crucial has one too. I consider both of these companies top of the line manufacturers. Samsung is another good brand, but I didn’t see any tool to help you select memory.

For these tools you need to know your mother board brand and model.

Summary

Upgrading or buying memory for a new computer is mostly a matter of matching numbers. The only science involved for what most of us want to do is knowing you need to match your memory to the motherboard and knowing how.

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