CPU-z question / MSI Diamond SLI

[sacrum]

Archived from groups: alt.comp.periphs.mainboard.msi-microstar,alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking (More info?)

Hi all,

Just a quick question....

I have clocked my system to HTT (FSB) 250mhz x 4 HT and 10.5 x 250 (AMD A64
4000) which is fine and the BIOS shows the mem frequency as 250MHz giving me
my 1:1 ratio - all good. However, if I use CPU-Z it shows my mem frequency
at around 236mhz....I'm baffled, any ideas?

My setup

AMD A64 4000 @ 2650
2x512 Corsair xms 3200 C2XL @ 250mhz (1T)
MSI K8N Diamond SLI (with latest BIOS)
2x Gigabyte GF6800 ultra's @ 425/1100
win xp pro (SP1)

Tia

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.msi-microstar,alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking (More info?)

sacrum wrote:
> Hi all,
>
> Just a quick question....
>
> I have clocked my system to HTT (FSB) 250mhz x 4 HT and 10.5 x 250
> (AMD A64 4000) which is fine and the BIOS shows the mem frequency as
> 250MHz giving me my 1:1 ratio - all good. However, if I use CPU-Z it
> shows my mem frequency at around 236mhz....I'm baffled, any ideas?

1:1 ratio on half-integer dividers doesn't work as might be intuitively
expected on A64s. What the CPU does is divide the CPU clock by an integer to
get the memory controller (ie memory bus) speed, such that the memory speed
is not ABOVE what it should be.

In you case, your CPU speed is 2625MHz. Ideally you want a 10.5 divider,
except it must be integer, so an 11 divider is used to get 238.6MHz. If a 10
divider was used then the memory speed would be 262.5MHz, above what it
should be.

A little app I've written:
http://www.emboss.co.nz/downloads/httopt-0.2.workinprogress.zip
will give you the numbers, and the documentation in
http://www.emboss.co.nz/downloads/httopt-0.1.zip
should give you a good idea of how things work.

[...]

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
Add michael@ to emboss.co.nz - My inbox is always open

 

[sacrum]

Archived from groups: alt.comp.periphs.mainboard.msi-microstar,alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking (More info?)

"Michael Brown" <see@signature.below> wrote in message
news:423c34b5$1@clarion.carno.net.au...
> sacrum wrote:
> > Hi all,
> >
> > Just a quick question....
> >
> > I have clocked my system to HTT (FSB) 250mhz x 4 HT and 10.5 x 250
> > (AMD A64 4000) which is fine and the BIOS shows the mem frequency as
> > 250MHz giving me my 1:1 ratio - all good. However, if I use CPU-Z it
> > shows my mem frequency at around 236mhz....I'm baffled, any ideas?
>
> 1:1 ratio on half-integer dividers doesn't work as might be intuitively
> expected on A64s. What the CPU does is divide the CPU clock by an integer
to
> get the memory controller (ie memory bus) speed, such that the memory
speed
> is not ABOVE what it should be.
>
> In you case, your CPU speed is 2625MHz. Ideally you want a 10.5 divider,
> except it must be integer, so an 11 divider is used to get 238.6MHz. If a
10
> divider was used then the memory speed would be 262.5MHz, above what it
> should be.
>
> A little app I've written:
> http://www.emboss.co.nz/downloads/httopt-0.2.workinprogress.zip
> will give you the numbers, and the documentation in
> http://www.emboss.co.nz/downloads/httopt-0.1.zip
> should give you a good idea of how things work.
>
> [...]
>
> --

Doh!

I have upped the voltage to 1.65 (9.5% on 1.50v) - new to msi, usually Asus,
and increased the multiplier to 11x250 and HT = 250mhz x 4. Just run cpuid
and spot on 250mhz freq for memory...thanks for help.....
> Michael Brown
> www.emboss.co.nz : OOS/RSI software and more
> Add michael@ to emboss.co.nz - My inbox is always open
>
>