RAM questions

rohan23

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My motherboard is an ASUS P5QL PRO. I am running 2 sticks of Kingston Hyperx 1GB RAM. They are DDR2 running at 333mhz each. They aren't dual channel. What is the major difference in running a dual channel to running my current setup? And what are the major differences in DDR2 667-800-and so on? Any suggestions on getting a new brand of RAM?
 
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Dual Channel allows the CPU to simultaneously send and receive information from your memory.

If you have DDR2 800MHz RAM it doesn't necessarily mean that you are getting that speed. If you're running Intel CPUs, most of the time you won't need anything higher than 667MHz because the rest is bottlenecked. However with some of the C2E and the new releases, RAM of speeds as high as 800-1066MHz can be fully utilized. If you want a more detailed explanation of how the CPU bottlenecks the RAM give me a PM or just post it.
 

worshipme

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Why aren't you running the RAM in dual channel? If you have two sticks, there should be one slot between the two.

RAM works in DDR. 333MHz = DDR 667.
 

rohan23

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Well, I tried running in dual channel. You know, putting each stick in the same colored slot. But, when I did that, I would have no display on my computer. It actually stops my graphic card from working. JogaBonito1502, so basically, what RAM would be good for gaming? I currently have Kingston Hyperx RAM. 2 1Gb sticks. Can you please explain to me how the CPU bottlenecks the RAM and what differences are in speed through the DDR2 RAM sticks. I.e. 667-800 and so on. Thanks!
 
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The reason DDR3 is not worth yet is because CPUs runs at FSB speeds lower than that of RAM. Take for example a 2.4GHz CPU (quad-core) that runs at 1333MHz. It is running at a FSB of 333MHz quad-pumped:

4 x 333MHz = 1333MHz

In order for a system to run as stable as possible the CPU FSB to RAM Speed ratio must be 1:1. So in order for you to run 1:1 with the CPU at hand you must have RAM that runs at 333MHz. Because DDR is dual data rate (not sure if I have the correct meaning of the acronym) you will divide the listed RAM speed by 2. To match the CPU FSB:

2 x 333 = 666 (667MHz DDR2 RAM)

Although you can get RAM running at speeds much faster than that (667MHz), you won't be fully utilizing it, therefore your CPU will be bottlenecking your RAM.

HOWEVER

If you can manage to alter the clock/multiplier combination of you CPU and keep it stable you, can get better performance out of your RAM. Since I'm going a little out of my range here, for the sake of the concept, we'll say that (using the previous CPU) 7 x 333 = 2400 (2331 in reality).

To run stable at stock settings this is what you will have:

CPU Multiplier: 7
CPU FSB: 333MHz
CPU Clock: 2.4GHz
RAM: 667

Now if you mess with the multiplier and FSB and you get it stable, you could have something like this (assuming you will keep the same clock speed):

CPU Multiplier: 6
FSB: 400MHz
CPU Clock: 2.4GHz

Now what will this allow? Because you're now using 400MHz as the FSB you can get faster RAM:

2 x 400MHz = 800MHz

Lastly, by changing the FSB to a higher speed you can increase the performace of your RAM (assuming you bought something that is being bottlenecked by the CPU). But beware, you can't just pop in numbers and hope it'll work well together. To change the settings you will have to do it little by little to keep it stable, you might even have to raise the VCore (voltage? Again out of my area) to power everything, thus emitting more heat and thus endangering your CPU even more.
I'm sorry I have to quote myself, but I'm short on time. I hope this will explain it to you.

edit: Here's more:

It is right. The RAM is most likely being bottlenecked by your processor. I'm going to go ahead and assume your processor has a 400MHz FSB (if quad-pumped). Before I explain it to you, I want to get it clear that DDR = Double Data Rate.

Ok, a quad-pumped processor is a processor that access the memory 4 times per cycle. So if it has a 400MHz FSB it would divide that into 4 to equally access the memory each pump during the cycle using 100MHz. Because DDR memory does 2 cycles for every cycle at the given speed it doesn't have to equally split the speed up to suffice for every pump. However you still need to take care of the 2 remaining pumps, so speed is cut in half to suffice for all 4 pumps. Therefore if you bought 400MHz RAM, at optimum level it could take care of 200MHz pumps. But because your processor only does 100MHz pumps, only half of that speed is utilized, and thus the principle of bottlenecking.

edit: Oh I guess I miss-read your question, your processor then is 800MHz, and the RAM is being utilized to its limit.
 

rohan23

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So, for my system, will there would be a significant difference between DDR2 800, 600 , or 1066? My ASUS P5QL PRO can run 1066 memory and the FSB can easily be overclocked to 1600.
 
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Because it is being bottlenecked by the CPU. My guess is that your CPU runs @ a FSB of 1333MHz quad-pumped. By my explanation this would limit your RAM to 667MHz.
 

Teny

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doesnt he have to OC to 400 on the FSB to run the ram speed at 800mhz?
 
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