Memory Frequency

[theguyisback23]

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

 

[jaquith]

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

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=3449#memory%20support%20list

 

[jsc]

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=3449#memory%20support%20list

 

[jaquith]

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