Archive for September, 2012

I’ve recently had to service and/or repair a few computers whose largest issue was that they had far too little RAM.  One in particular was running Windows 7 Pro and had only 512mb of RAM – this half the required memory for this operating system.  So either the person who installed Windows 7 on this computer wasn’t aware how much RAM it had or wasn’t aware that that it would take a severe performance hit for not having enough of it.

What is RAM?

Example of RAM memory chips

RAM stands for Random Access Memory.   Don’t worry too much about the name.  It refers to the way in which RAM stores information and isn’t technically accurate for modern types of RAM anyway but the name has stuck.

What you DO need to know is that RAM is temporary memory where your computer can store information that it’s thinking about or working on while it is turned on.  It is volatile memory – meaning that it will not be retained when the power source is disconnected.   RAM is also pretty fast memory for the computer to read and write to.  Information stored in RAM can be worked on and accessed very quickly.

Computers generally use RAM for storing the current applications you have open for quick access and the documents or files you have open.  What sits in the RAM is controlled by the operating system.

You can think of RAM like having a large open desk with lots of clear space when you begin work.  If your desk is large enough, you can layout all the resources and equipment you need to perform your work.  If your desk is too small you end up shuffling things around, moving them on and off you desk and stacking things up.

In much the same way, if a computer has plenty of ram it has space to work.  Space to hold all the resources it needs at the given moment and quick access to the information it is working on.  It doesn’t need to shuffle things off onto your hard drive or constantly re-arrange things in ram to have access to the information it needs.

What’s with all these numbers and acronyms like DDR and GB?

(You can skip this part if you want to avoid technical explanations but I’ll try to make it as painless as possible).

This is where it can get confusing…

Firstly, your ram will come in a certain size or amount of Ram – eg. 2Gb, 4Gb, 16Gb etc.  Gb is short for Gigabyte and is a measure of now much information your RAM can store.

SDRAM, DDR1, DDR2, and DDR3 are different types of ram.  Think of this like models of cars.  Actually it’s more like the engine model in your car.  Not all engines will work in all cars.  In a similar way your computer will only be able to take certain types and speeds of ram and if you’re not sure – it’s best to check with a computer technician before buying new ram.

Along with the type, ram runs at a certain speed and with certain timings (hold onto your brains for this part).  Ram that is labelled “DRR3-400” means it is type DDR3 and runs at a maximum frequency of 400Mhz.   This is sort of a ‘how many things a second’ can you manage rating.

Sometimes there is also information given about data transfer rates of the ram and timings. Most often these are given as a series of numbers E.G. CL7-7-7-18.  These numbers indicate the number of clock cycles the ram will take to perform certain tasks.  Generally speaking the lower the numbers, the tighter the timings are and the more expensive the ram will be.

Data transfer rates are usually noted with a ‘PC’ suffix.  PC3200 ram for example runs at 3200 megabytes per second.

Why do I need ram?

Computers use ram to store information on a temporary basis.  Usually for calculations or holding documents that you are working on and programs that you have open so you can work on them and switch between them quickly.

If your computer runs out of ram it uses a portion of your hard drive space as ram – this is called a SWAP file or partition.  Hard drives are slower than ram so you can see a performance drop if you run out of Ram and the computer starts using hard drive memory – especially if it has to do this on a consistent basis.

As I mentioned in the introduction, if you have plenty of sufficiently fast ram, your computer has the space it needs to work and can access the information it needs more quickly.   Overall, the appearance it gives is that of an overall faster computer.

How much RAM do I need?

There are 2 equally true and equally cliche answers to that question.

1. It depends

2. The more the better (to a point)

Let me start with a baseline.  Your operating system requires a certain amount of RAM and Microsoft publish recommendations on the amount of RAM you should have for each of their operating systems. Although Microsoft calls this the recommended amount, I would suggest thinking of it more as a minimum for acceptable performance.

Once you get past the requirements for your operating system, you need to have some for your programs.  The more memory hungry your programs are (3d games, video processing etc) the more you will need.   Also the more you have open at any one time, the more you will need.

Note: Unless you are running 64bit operating system, you will not see any benefit for anything above 3Gb of ram as your system cannot recognise more than 3Gb.

At the time of writing this, computers currently come with 2-4GB ram.  If you don’t have this much in your computer currently, you should consider upgrading.  Especially if it seems slow or takes a long time to respond.

If you have a 64bit operating system and you run memory intensive applications or have a lot of applications open you may see a benefit of increasing your ram up to 8Gb or more.

References and further reading:
Windows XP System Requirements – http://support.microsoft.com/kb/314865
Windows Vista System Requirements – http://windows.microsoft.com/en-us/windows-vista/products/system-requirements
Windows 7 Systems Requirements – http://windows.microsoft.com/en-us/windows7/products/system-requirements
eHow – How to read memory chips – http://www.ehow.com/how_7289009_read-memory-chips.html

Toms Hardware – PC Memory http://www.tomshardware.com/reviews/pc-memory,1698.html