FSB:DRAM Help

[JonD]

On CPU-Z its showing my FSB: DRAM as:

2:3.

Is this correct?

I have no idea what this ratio means so can someone explain.

My other settings being displayed are:

Frequency: 400Mhz
CAS# Latency: 5
RAS# TO CAS# Delay: 5
RAS# Precharge: 5
Cycle Time (Tras): 12

Also if I goto my SPD tab it displays:

Timings table (Column 1)

Frequency 277
CAS: 4.0
RAS to CAS: 4
RAS: 4
Tras: 4
TRC: 15

Timings table (Column 2)

Frequency 400
CAS: 5.0
RAS to CAS: 5
RAS: 5
Tras: 18
TRC: 12

It looks like column 1 is wrong.... How can I fix?

Nothing is overclocked by the way.

Thx

 

[thefishdude]

2:3 is a ram divider, you tale the fsb of your cpu soo 267 at stock on conroe. you then divide that by the first number. multiply it by the second number and then double it.

soo

267 / 2 x 3 = 400 this is doubled for ddr2 memory so your memory is running at 800mhz with settings of 5-5-5-12. it seems.

dont knw about the otehr 2 bits you mentioned.

 

[simonnance]

the columns display the stock settings that the ram has, and they are set such to allow high performance ram to automatically run on rigs that can't support their high frequencies, timings, or voltages.

Kinda a "default safe" setting.

 

[JonD]

So the 2 columns are normal? Dont they represent each stick of RAM?

Its displaying the second stick is running fast than the first.



Thx

 

[Mole]

So the 2 columns are normal? Dont they represent each stick of RAM?

Its displaying the second stick is running fast than the first.

Looks like the columns are normal, though I'd expect column 1 to be 267MHz rather than 277MHz. It's telling you what timings the memory is capable of at different speeds. So, as you might expect, the memory can run lower timings at lower speeds. Manufacturers build in more than one set of timings into the timings table so that the BIOS can consider what timings to use for a given speed (which is normally the column whose frequency is closest to, but higher than, the speed you want to run your memory).

Both sticks will be running at the same speed and as thefishdude said that will be 400MHz DDR (i.e. 800MHz) with timings of 5-5-5-12. This comes from the first tab that tells you your FSB : DRAM ratio. The BIOS has used column 2 to determine the highest speed the memory is capable of.

It is there to prevent guesswork. Suppose your memory can run CAS latency of 5 cycles at 400MHz. You might expect that it can run CAS latency of 5 * 0.67 = 3.33 cycles at 267MHz. However, can it run CAS latency 3 or does it require 4? The manufacturer knows, but the BIOS doesn't. It cannot round down as this is unsafe. It has to round up to 4 which is slower. Some RAM might be able to run 3, so this would be specified in the timings table of the RAM and can be read by the BIOS.

Hope this helps,

Martin