[Albert Lionheart]

There is a thread running about how much RAM for 32 or 64 bit OSs (RAM quantity), but where there is a limit imposed either by the board or the OS, it would be interesting to know more about the benefits of different sorts of RAM, and also to understand why there are different names for the same thing?
How do I choose the fastest memory modules for my system, and what is the difference between PC2 memory and say DDR2?

[Joshuashawharvey]

PC2 and DDR2 is the same thing mate. For example PC2-6400 is DDR2-800. PC2-6400 is it's real model name, but DDR2-800 which is the standard name, is easier to understand for most people.

Choosing the fastest modules for your board is easy, just check what RAM is compatible with your motherboard. Yours can support 8GB of PC2-8500 (DDR2-1066) so that would be the best RAM you could get.

[Albert Lionheart]

Thanks Joshua - great help.
Next question - how do I know from the spec that one piece of memory is better than another of the same type - say Kingston DDR2-667 is better than Crucial DDR2-667? And what is the reference to EC - some is non-EC and unbuffered, or not as the case may be?

[Howard]

Most mobo manufacturers offer recommended ram brands and specs. The rest is upto you to decide which ram you prefer. Reading reviews is one way to determine which ram you think is best.

As for the ECC bit:

Unbuffered Memory

As I was testing the different memory types, I was curious how Sisoft Sandra would interpret the differences. I decided to include a small screenshot for giggles.

There really isn't a lot to say from a technical perspective about unbuffered memory. It's what the vast majority of PCs on the planet use. Essentially, with unbuffered memory the chipset deals directly with the memory itself. There is nothing in between the two parties as they communicate.

Registered Memory

Registered memory is where the fun begins. I have defined in the past, wayyy back in my Iwill DVD266-R review. I'll use the same quote I did then:

"Registered modules have additional components (registers) placed between the incoming address and control information and the SDRAM components. These modules are typically used in Servers due to their added reliability (they place much less of an electrical load on the memory controller and therefore make it possible to have as many as 16 or 32 modules in a large system)."

Regards Howard

[Albert Lionheart]

Bril - thanks Howard - muich clearer now!
Looking at the book of words that came with the board, although it is supposed to support DDR2-1066 there are none listed - just the 800 and 667 MHz stuff.
What I bought is on the 'approved' list so I guess it is OK!!

[Joshuashawharvey]

Well what I read, your board only supports DDR2-1066 with an O/C, so you're probably better off with DDR2-800.
RAM timings are also a thing you should look for in RAM, the lower the better, so RAM with timings of 4,4,4,12 would be better than say 5,5,5,15 which is usually the bog standard. It's hard to explain how these timings work, but just look for lower ones for faster, more stable RAM. If it is DDR2, never settle for more than 5,5,5,15 timings.

[Albert Lionheart]

Now I am confused!
this is the spec of this memory and I cannot see any reference to timings except for CL5 - wassit all mean??

[Joshuashawharvey]

CL5 means 5,5,5,15. CL means CAS (Column Access Strobe) Latency. CAS is the first number which is 5, and it usually follows with 5,5,15 when the CAS is 5. I know it's confusing lol, but the lower the latency or CL, the better.

[Albert Lionheart]

So would I notice the difference between CL4 and CL5?

[Joshuashawharvey]

Well in a benchmark you might see a very slight increase in bandwidth, but it's more on the stability side you may see an improvement. Also you will probably be able to get a higher overclock with RAM with lower timings.