Help me, about RAM ratio and memory

goldcomputer

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Jul 23, 2007
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I have:
MAINBOARD: ASUS P5GZ-MX
CPU: INTEL 3GHZ 531 BUS 800MHZ
RAM: 2 module 512MB DDRII-533MHZ are running dual channel
FSB:DRAM is 3:4

1/
I don't know that is the FSB:DRAM ratio ok?
Should I set it to 1:1?
Please give some advice to overclock or optimize my system. :)

2/ In my mainboard manual was wroten that
"Memory: Dual-channel memory architecture
2 x 240-pin DIMM sockets support up to 2GB of unbufferred non-ECC 533/400 Mhz DDR2 DIMMs"
Now, if I attach to mobo 2 module 1GB (total=2GB) then will the memory be running dual channel and will the memory total be 4GB (effective speed)?

Thanks for reading.
 

menetlaus

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Jul 19, 2007
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The 4:3 ratio is correct (both CPU and Ram are Quad or Dual "pumped" so the 800 / 533 aren't the base numbers - it's actually 200 MHz CPU and 266 MHz ram) So with a 4:3 ratio - the 200 from the CPU gives a 266MHz FSB for the ram (266 "double-pumped" gives the stock 533MHz Double Data Rate)

I don't understand your Ram question, you already have 2 - 512MB sticks for a total of 1GB, and if you add 2 more 1GB sticks you will have 3GB total memory not 4GB (and GB is size and has nothing to do with effective speed).

 

goldcomputer

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Thanks for your answer.
I mean that I will remove 2 modules 512MB, after, I attach 2 other modules 1GB.

Let I ask you more: somebody said that the ratio 1:1 is the best, so should I set the FSB:DRAM ratio from 3:4 to 1:1 ?
 

menetlaus

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From what I've heard, 1:1 is preferred because it's synchronized. So when the double data rate ram "talks" to the quad-pumped CPU - every other "pump" for the CPU gets additional information to or from the ram.

Where any other ratio (like say 4:3) only the first "pump" is in sync with the ram and the others don't line up as well (the data still gets through, but if the CPU was waiting on some info from ram - it has to wait another 1/4 cycle to get it.)

But with CPU speeds as fast as they are, and all the improvements in memory controllers... your a lot better off with DDR2-533 and a 4:3 ratio than running 1:1 (with DDR2-400)