REDUX: A7V8X-X Memory Speed Settings (strangeness)

  • Thread starter Thread starter Ohaya
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Ohaya

Hi,

More research and more tweaking.

I've finally noticed something re. the relationship of the BIOS Frequency
and Memory Speed settings.

It appears that under certain circumstances, there is a rational
relationship between the Frequency setting and the minimum Memory Speed
setting.

In particular, if the PCI part of the Frequency setting is less than or
equal to the actual CPU's, then the minimum Memory Speed setting is 2x the
FSB part of the Frequency setting.

For example:

Frequency Memory Speed (min.)
120/33 240
121/33 242
122/33 244
etc.

The "strangeness" part (i.e., the part that I don't understand) is that for
PCI frequency of 33, the minimum combination "choices" for Frequency setting
offered by the BIOS is 120/33.

At the same time, in my case, with a Duron 850 CPU, the Frequency setting
defaults to 100/33 (which is correct).

In other words, in my BIOS, with the Duron 850, the Frequency choices "jump"
from 100/33 to 120/33:

100/33
120/33
121/33

So what's going on?

Why does Frequency 100/33 => Memory Speed 266?

And, what happened to 101/33, 102/33, etc.?

Unless I'm missing something (i.e., am unaware that there's some reason why
101/33, etc. are not valid), this seems like a bug in the BIOS (V1008)?

So I'm wondering (again) if any of you out there have an A7V8X-X with a BIOS
with version less than V1008 (e.g., 1007, etc.), do you see choices for
101/33, etc.?

Jim
 
Ohaya said:
Hi,

More research and more tweaking.

I've finally noticed something re. the relationship of the BIOS Frequency
and Memory Speed settings.

It appears that under certain circumstances, there is a rational
relationship between the Frequency setting and the minimum Memory Speed
setting.

In particular, if the PCI part of the Frequency setting is less than or
equal to the actual CPU's, then the minimum Memory Speed setting is 2x the
FSB part of the Frequency setting.

For example:

Frequency Memory Speed (min.)
120/33 240
121/33 242
122/33 244
etc.

The "strangeness" part (i.e., the part that I don't understand) is that for
PCI frequency of 33, the minimum combination "choices" for Frequency setting
offered by the BIOS is 120/33.

At the same time, in my case, with a Duron 850 CPU, the Frequency setting
defaults to 100/33 (which is correct).

In other words, in my BIOS, with the Duron 850, the Frequency choices "jump"
from 100/33 to 120/33:

100/33
120/33
121/33

So what's going on?

Why does Frequency 100/33 => Memory Speed 266?

And, what happened to 101/33, 102/33, etc.?

Unless I'm missing something (i.e., am unaware that there's some reason why
101/33, etc. are not valid), this seems like a bug in the BIOS (V1008)?

So I'm wondering (again) if any of you out there have an A7V8X-X with a BIOS
with version less than V1008 (e.g., 1007, etc.), do you see choices for
101/33, etc.?

Jim
Click to expand...

Hi,

I finally got ahold of Asus Tech Support, and I was wondering if the
"theory" that they gave me makes any sense:

According to them, the reason that the BIOS doesn't allow me to set the
Memory Speed to 200 is that I have PC2700 memory, and that I can't
underclock the PC2700 to 200 MHz. Their theory is that if I used PC1600, or
possibly, PC2100 memory, that the BIOS would allow me to select 200 as the
Memory Speed.

Does the above "jive" with anyone's experience?

Also, if the above is the case, then the BIOS is detecting the memory specs,
presumably by SPD (I do have the BIOS set for "by SPD"). Then, if that is
the case, if I change the "by SPD" to "Manual", is there some setting that
will allow Memory Speed to be set to 200?

Jim
 
PC2700 is 166MHz so how could you"underclock" it at 200MHz?
You cant get 166MHz ram to run at 200MHz and you cant get 133MHz ram to run
at 200MHz.
DDR333 ram is double clocked (166x2)
DDR266 is ^ ^ (133x2)
PC2100 is 133MHz so again how could expect to run at 200MHz?
 
Noomie said:
PC2700 is 166MHz so how could you"underclock" it at 200MHz?
You cant get 166MHz ram to run at 200MHz and you cant get 133MHz ram to run
at 200MHz.
DDR333 ram is double clocked (166x2)
DDR266 is ^ ^ (133x2)
PC2100 is 133MHz so again how could expect to run at 200MHz?
Click to expand...

They probably meant 2x100 = 200?
 
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