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Memory Frequency

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September 25, 2010 5:54:41 PM

I don't know how to calculate my ddr3 bandwidth and speed at all
but on cpuz i get the followings:
dram frequency 400mhz
and the timings are 7-5-5-16 by my OC
have no idea how can actually these 1600mhz 3x1gb get used by my e4500 at full speed without OC' CPU

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a c 347 } Memory
September 26, 2010 5:00:52 AM

EDITS - Oops! Little confused, but CPUz makes mistakes often. Yes, I indeed did overlook this is a 775 socket CPU. :ange: 

The Core 2 Duo E4500 has a FSB of 800 MHz, so the Memory Multiplier is 4; see chart.

Your question, "1600mhz 3x1gb" - by default DDR will run at 1066 MHz.

BCLK X 4 = FSB
BCLK X Memory Multiplier = DRAM Rate

FSB:
1333 / 4 = 333
1600 / 4 = 400

RAM:
667 / 2 = 333
800 / 2 = 400
1066/ 2 = 533

Asynchronous to the FSB:
1:1 = 333 MHz : 667 MHz
4:5 = 333 MHz : 833 MHz
2:3 = 333 MHz : 1,000 MHz
5:8 = 333 MHz : 1,066 MHz

B_CLK times four is your FSB (once again, Front System Bus); B_CLK times your memory multiplier is your DRAM rate; B_CLK times your CPU's multiplier is your CPU frequency.

BIOS Changes:
1. Memory Multiplier = 4 {Some BIOS calulate this and give a drop-down menu - {1600 Mhz}
2. CAS Settings = 7-7-7-16
3. {Verify Auto} or set DRAM Voltage per spec'd DDR {e.g. 1.65V}

In any case unless your BIOS fully recognizes you exact Part-Number XMP DDR then don't use XMP; BSOD/Post Failure/Unstable system will result otherwise. Example, XMP {MOBO Certified Memory Support List} - http://www.gigabyte.us/products/product-page.aspx?pid=3...
a b } Memory
September 26, 2010 5:41:58 AM

jaquith said:

Little confused, but CPUz makes mistakes often. Not really. You just need to understand what it is trying to tell you. :) 

DRAM Frequency of 400 MHz is generally 800 MHz DDR2 speed {Double Data Rate}. or 1600 MHz DDR3 speed.

Your question, "1600mhz 3x1gb" - by default DDR will run at 1066 MHz. If memory settings are on Auto, your memory will run at SPD settings.

Calculation: {Memory Multiplier = Round Down ( DDR Speed / BCLK)} Not really. E4500 is a Core2 CPU, uses FSB, not BCLK.
Sock - Memory Multiplier = (1066 MHz / 133.33 MHz) = 8 No BLCK, doesn't apply.
therefore Memory Multiplier =(1600 / 133.33) = 12

BIOS Changes:
1. Memory Multiplier = 12 {Some BIOS calulate this and give a drop-down menu - {1600 Mhz} If it is a Gigabyte board, take the memory settings off Auto and set Memory Multiplier to 4. That will give you a memory clock four time the FSB frequency, just what you need to run your FSB:RAM ratio at 1:1.

2. CAS Settings = 7-7-7-16
3. {Verify Auto} or set DRAM Voltage per spec'd DDR {e.g. 1.65V}

In any case unless your BIOS fully recognizes you exact Part-Number XMP DDR then don't use XMP; BSOD/Post Failure/Unstable system will result otherwise. Example, XMP {MOBO Certified Memory Support List} - http://www.gigabyte.us/products/product-page.aspx?pid=3...

a c 347 } Memory
September 26, 2010 7:13:50 AM

^ Yep! - oopsy {1366 vs 775} They are a pain to calculate; I use an Excel spread sheet. Autopilot crash!
!