Extra RAM

Hi,
Can someone help me through the minefield of buying extra RAM?

According to my specs I have: 512mb DDR2 533mhz
I ran CPU Z which states: DDR2, PC2-5300 (333 MHz), 512 MBytes, Nanya Technology
Having emailed my CPU Z report to Crucial, they say I need: PC5300 DDR2 667mhz
Firstly I am confuse over whether it is 333, 533 or 667mhz.
Secondly, how important is it to have identical sticks?. The installed seems to be Nanya Technology.
Orca recommend Trancend. Neither of these are listed by Asus as being recommended for my mboard. The Crucial part number recommended in the Asus manual is different to that recommended by Crucial, based on the CPU Z report.
Does it really matter what make it is as long as it is the same spec?
Finally, I am confused over single chanel/ dual chanel.
I assume, as I have only one stick, I have single chanel. If I add another stick in the appropriate slot, will this give me dual chanel, and will I see a noticeable performance improvement?

Your CPU-Z report and the Crucial recommendation are for the same specification of RAM.
DDR2 memory uses 2 memory sticks to effectively double the amount of data that can be processed in a given period of time. The numbers are confusing but I'll do my best. Basically, your memory bus runs at 333MHz, but twice the number of inputs/outputs are possible per cycle ie. 667MHz. To confuse matters further, DDR2 builds on DDR which already effectively doubles the memory clock speed which, here, is 166MHz.
5300 comes from the peak transfer rate possible, about 5300MB per second.
Have a look here http://en.wikipedia.org/wiki/DDR2_SDRAM. It explains how DDR2 memory works. The table about a third of the way down the page shows how the numbers relate to one another.
Dual channel doesn't actually specify that identical memory modules are used. It's usually recommended though. Check that you can return what you buy if it doesn't work as you want it to. Do check as well that your board supports DDR2. If you do buy a matched pair of modules, 2x1Gb sticks are the best value. Have a look at the page below for details of the dual channel memory specification http://en.wikipedia.org/wiki/Dual_channel.
If your motherboard supports it, there is a benefit to be had from DDR2 memory. It relates to the rate at which data is processed eg. PC5300 is 'better' than PC4200. DDR2 is twice as 'fast' as DDR which is twice as 'fast' as 'normal' RAM. It depends on what you are doing. Using Word and web browsing won't improve. Playing modern games with a modern CPU and GPU will benefit. It's quite likely that the CPU finds itself 'waiting' for data with slow RAM and a DDR2 setup will reduce this bottleneck. There is quite a gain to be had by increasing the amount of memory you have too, especially with Vista (if you still use '98, you'll need a hack, and there's little reason to go beyond 768Mb.)
Crucial have a memory selector on their web site that will list the RAM options for your motherboard, but if you want a stick to match what you already have, the advice you were given seems reasonable. I'd advise getting a matched pair of 1Gb if finances allow.
I hope this helps.

Thanks DrATty,

That really is a great help.

Buy a Dual Channel Kit, these will be a matched pair, guaranteed to work, and guaranteed for LIFE.

Geil, OCZ and others are the ones to aim for, Crucial as well, but theres a premium price to have there name tag, nto really worth it IMHO.

for best prices check www.microdirect.co.uk

Quote:

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Originally Posted by ukengineer

Buy a Dual Channel Kit, these will be a matched pair, guaranteed to work, and guaranteed for LIFE.

Geil, OCZ and others are the ones to aim for, Crucial as well, but theres a premium price to have there name tag, nto really worth it IMHO.

for best prices check www.microdirect.co.uk

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I agree. A matched kit would be best and will avoid any headaches.
A recent lab test in Custom PC recommended the Corsair TWIN 2X2048-6400 kit as their budget buy at £66-55 from Scan. You need to make sure you buy compatible RAM but at today's relatively cheap prices, 2Gb is a steal -it's at a price sweet spot. It would quadruple the memory you have now and open the path to 4Gb if and when you want to go there. I think too that you'll find going to 2Gb will give you a marked performance boost beyond that you would see with 1Gb, especially with newer games. Don't worry to much about planning to move this RAM to your next PC - technology is moving too fast and something new will have come along by then. DDR3 is next and doubles the speed once again.
With respect to your query concerning the memory you saw not being listed as compatible with your motherboard, I wouldn't worry too much. If you buy from a decent supplier, they will guarantee that what they sell you will work. The list (QVL or Qualified Vendor List - the spelling is different on many web sites but the meaning is the same) for my motherboard is rather short and doesn't include the memory I have. My PC runs perfectly.
Have fun, Andy.

Thanks for the good advice guys.

Rob