RAM upgrade help

[codygriffy]

To start off. If anyone has a link to a thread so I don't have to ask so many questions about building computers and which parts are compatible, please let me know.

Here is my motherboard http://www.asrock.com/mb/NVIDIA/K10N78/

I believe I currently have 2 x 2 gig Kingston pc2-6400 800 mhz in it, bios says it is only at 400 mhz though <-- something to do with internal speed i take it?

THE GOAL - I would like at least 8 gigs of memory in this rig. What is my best solution?


Forgot to add 

Processor: AMD Phenom(tm) II X4 920 Processor (4 CPUs), ~2.8GHz

 

[jsc]

The simple thing to do is to put another pair of the same memory into the motherboard.

"pc2-6400 800 mhz in it, bios says it is only at 400 mhz though":
All three specs mean the same thing.

"PC2-6400" means DDR2 RAM with a throughput of 6400 megabits/second. "DDR2-800" means the RAM is clocked at 800 MHz. "400 MHz" is the RAM frequency. Clock and frequency are not the same.

Brief tutorial follows:

"Definition time (attention purists, I'm talking about DDR2, Intel CPU chips, and I'm simplifying a little ):

Core2 CPU's use a frontside bus (FSB). The FSB is a thing with two main characteristics: speed which is usually defined in MHz and width which in the Core2's is 64 bits wide. We are concerned with the speed.

Using the Q6600 as an example, the FSB frequency is 266 MHz. The matching DDR2 memory clock for that frequency is 533 MHz (266 X 2). DDR2 memory transfers two chunks of data for each bus cycle, hence double the frequency. So, to run 1:1 at an FSB of 266 MHz, we need DDR2-533 RAM. What CPUZ does is a little confusing. It will tell you that the memory frequency is 266 MHz for a 1:1 ratio.

The FSB clock is 1066 MHz (266 X 4). The bus is "quad pumped". It transfers 4 chunks of data into and out of the CPU each bus cycle. So each FSB cycle generates 4 FSB clocks.

Now, if you increase the FSB frequency to 333 MHz, the corresponding memory clock is 667 MHz and the FSB clock is 1333 MHz."

And a short tutorial on computer building:
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step-guide-building

 

[codygriffy]

Best answer selected by codygriffy.

 

[codygriffy]

The simple thing to do is to put another pair of the same memory into the motherboard.

"pc2-6400 800 mhz in it, bios says it is only at 400 mhz though":
All three specs mean the same thing.

"PC2-6400" means DDR2 RAM with a throughput of 6400 megabits/second. "DDR2-800" means the RAM is clocked at 800 MHz. "400 MHz" is the RAM frequency. Clock and frequency are not the same.

Brief tutorial follows:

"Definition time (attention purists, I'm talking about DDR2, Intel CPU chips, and I'm simplifying a little ):

Core2 CPU's use a frontside bus (FSB). The FSB is a thing with two main characteristics: speed which is usually defined in MHz and width which in the Core2's is 64 bits wide. We are concerned with the speed.

Using the Q6600 as an example, the FSB frequency is 266 MHz. The matching DDR2 memory clock for that frequency is 533 MHz (266 X 2). DDR2 memory transfers two chunks of data for each bus cycle, hence double the frequency. So, to run 1:1 at an FSB of 266 MHz, we need DDR2-533 RAM. What CPUZ does is a little confusing. It will tell you that the memory frequency is 266 MHz for a 1:1 ratio.

The FSB clock is 1066 MHz (266 X 4). The bus is "quad pumped". It transfers 4 chunks of data into and out of the CPU each bus cycle. So each FSB cycle generates 4 FSB clocks.

Now, if you increase the FSB frequency to 333 MHz, the corresponding memory clock is 667 MHz and the FSB clock is 1333 MHz."

And a short tutorial on computer building:
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step-guide-building

Thank you!