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Discussion Starter · #1 ·
Ok I have a 4:3 fsb:dram setting happening right now. I am showing a freq of 169.1 Mhz in cpu-z my mem is 667mhz sticks. does this mean that my mem is really running at 338.2Mhz or what? is a 4:3 divider good? I am able to overclock farther right now than ever before with a 1:1.

i've read all the faq and quides, and still don't fully understand, sorry(maybe i'm thick in the head)

just an update: Before when I was running 1:1, I couldn't OC any more than 3.56ghz. Now that I'm running a 4:3 divider, I am at 3.74ghz and still climbing.
 

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Common Options : 1:1, 3:2, 3:4, 4:5, 5:4

The choice of options in this BIOS feature depends entirely on the setting of the DRAM Ratio H/W Strap or N/B Strap CPU As BIOS feature.
When DRAM Ratio H/W Strap has been set to Low, the available options are 1:1 and 3:4.
When DRAM Ratio H/W Strap has been set to High, the available options are 1:1 and 4:5.
When N/B Strap CPU As has been set to PSB800, the available options are 1:1, 3.2 and 5:4.
When N/B Strap CPU As has been set to PSB533, the available options are 1:1 and 4:5.
When N/B Strap CPU As has been set to PSB400, the only available option is 3:4.
The options of 1:1, 3:2, 3:4 and 4:5 refer to the available CPU-to-DRAM (or CPU
RAM
) ratios.

Note that while the Pentium 4 processor is said to have a 400MHz or 533MHz or 800MHz FSB (front side bus), the front side bus (also known as CPU bus) is actually only running at 100MHz or 133MHz or 200MHz respectively. This is because the Pentium 4 bus is a Quad Data Rate or QDR bus which transfers four times as much data as a single data rate bus.
For marketing reasons, the Pentium 4 bus is labeled as running at 400MHz or 533MHz or 800MHz when it is actually running at only 100MHz, 133MHz and 200MHz respectively. It is important to keep this in mind when setting this BIOS feature.
For example, if you set a 3:2 ratio with a 200MHz (800MHz QDR) CPU bus, the memory bus will run at (200MHz / 3) x 2 = 133MHz or 266MHz DDR.
By default, this BIOS feature is set to By SPD. This allows the chipset to query the SPD (Serial Presence Detect) chip on every memory module and use the appropriate ratio.
It is recommended that you select the ratio that allows you to maximize your memory modules' capabilities. But bear in mind that synchronous operation using the 1:1 ratio is also highly desirable as it allows a high throughput.

THe reason your able to OC higher now with your ratio at 4:3 is because its not trying to push the RAM to such a high frequency as when it was at 1:1, 1:1 means your mem is running at whatever freq that your FSB is, when 4:3 its running 25% less than what it would have been running at 1:1.
 

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Discussion Starter · #3 ·
thanks for a good explanation, I now understand the dividers affect on ram. +rep for you my friend.

my ram is 667mhz, but my divider has it running at 167mhz according to what you just told me. Other than changing the multiplier, is there another way to up the memeroy bus? Also does tightening the timings make up for the lower speed?
 

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lucid: but doesnt the multiplier indicate that the 133/xxx fsb speed is running how many ever times ur multiplier is set to, so 133x15.1(just example may not be probable) is running 133 15 times giveing the total fsb?
 

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Quote:


Originally Posted by ptrogen

lucid: but doesnt the multiplier indicate that the 133/xxx fsb speed is running how many ever times ur multiplier is set to, so 133x15.1(just example may not be probable) is running 133 15 times giveing the total fsb?

no the multiplier is for tha cpu, you multiply the FSBxMulti to get final clock speed... like 200fsbx15multi=3ghz
 

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Quote:


Originally Posted by pbasil1

no the multiplier is for tha cpu, you multiply the FSBxMulti to get final clock speed... like 200fsbx15multi=3ghz

Close... FSB = external clock speed x 4 for P4s. Clock speed = external clock speed x multiplier.
 
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