Noobie Divider Help Please

[DublinGunner]

It really depends on which way you want to work out your ram speed.

 

The 15 is the ration of ram speed to cpu speed, i.e cpu speed/15 = ram speed, (when using 10x CPU multi, and 7/10 divider) 10x10/7=100/7=14.28=15 (always go to next next higher integer.

 

I however dont work our my ram speed this way, as I think deducing the ram speed as a function of the FSB (LDT) is more accurate. i.e if using the 7/10 divider, and your FSB(HT) is 290, then 290*7/10=2030/10=203mhz.

 

Even different programs you use (Everest etc) will report your ram at being different speeds.

[Pdog]

Thanks everyone for there help. I think I slowly understand

 

 

Pdog

[DublinGunner]

It appears you have the 1/2 divider selected. Could you go into the BIOS and confirm that you have the 7/10 divider selected.

 

Everest is even saying that the FSB:RAM is 20/10

[ooztuncer]

@pdog: first of all u are still on the 1:2 divider thats why they show 145. Secondly, if you use 7:10 divider your ram will be working on 193 fsb (not 203 - it's not like 290x7/10) - here is the explanation of the memory speed under overclocking guide:

 

Originally Posted by Sharp

How to calculate your memory frequency

 

Memory Frequency = (FSB x (CPU ratio)) / ] ((CPU ratio) x (FSB : DRAM ratio)) [

 

Ceiling function is shown with ][,

eg

]10.1[ = 11

]10.2[ = 11

]-6.2[ = -6

]-8.9[ = -8

 

For positive numbers always round up to the nearest whole number.

For negative numbers always round down (its actually still up) to the nearest whole number.

 

Big example

FSB = 290

CPU ratio = 7

DRAM:FSB ratio = 5:6, re-arrange to 6:5 (FSB : DRAM)

 

Using the formula,

Memory Frequency = (FSB x (CPU ratio)) / ] ((CPU rato) x (FSB : DRAM ratio)) [

 

Memory Frequency = (290 x (7)) / ] ((7) x (6/5)) [

 

Work this bit out first

] ((7) x (6/5)) [

 

6/5 = 1.2

 

and that becomes

] (7) x (1.2) [

 

7 x 1.2 = 8.4

 

Now remember the ceiling function, ][

 

]8.4[ = 9

 

Put that back into the main formula

 

Memory Frequency = (290 x (7)) / 9

 

So

Memory Frequency = (290 x 7) / 9

= 225.5Mhz.

[Pdog]

Hi Peeps,

 

Just to confirm these are the settings I am using:

 

DRAM Frequency Set 140=RAM/FSB: 07/10

 

So my Memory Bus is running at 193.

 

The only thing that confuses me know on the POSt screen it states CPU- Memory Information DDR280. I assume I am just getting confused by this.

 

In CPU-Z under the memory tab, Timings The frequency and FSB:DRAM are greyed out.

 

However Everest is reporting 207mhz, although I know that this is rounded up.

 

 

Thank you both for your patience in explaining this to me.

 

 

Pdog

[ooztuncer]

The only thing that confuses me know on the POSt screen it states CPU- Memory Information DDR280. I assume I am just getting confused by this.

 

...However Everest is reporting 207mhz, although I know that this is rounded up.

 

Because u are using 7:10 divider, at the initial post screen it multiplies 400 (2x200mhz(ddr issue) - stock speed) by 7:10 which gives 280. If you use 1:2 it will show 200, likewise if you use 3:4 it will show 300.

 

However, I didnt understand why u are getting 207 under everest and cpu-z. If ur running at 10x290 with a 7:10 divider it should show 193... interesting

[DublinGunner]

Thats because some programs dont use the more complex method of working out the memory frequency, as I stated earlier.

 

I always use the more simple method when working out which divider to use. Its quicker, and you do not need to be that accurate.

 

I happen to think that simply multiplying the FSB(HT) speed by the divider will give you the actual speed, as the memory bus is calculated as a function of the FSB speed, not the CPU speed. Its from the FSB that the memory bus gets its operating frequency