FSB not running at potential speed

[Guest]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Hey all-
I'm running an AMD Athlon Thunderbird, which according to the specs is
1.33ghz with a 266mhz FSB on an ASUS a7n66-vm, which supports 200 and 266
mhz FSB's. Anyway, according to two diagnostic programs, the it's running at
1.33ghz like normal, but only 133mhz on the RAM. What's weird is:
..EVEREST Home Edition says that the CPU is running at 133 on the FSB.
..Belarc Advisor says the circuit board supports 133mhz.
..The ram itself is Elixir, and should run at 333mhz at most.

So what's the deal? I'm not sure if it's always been like this. There's
nothing in the BIOS to work with because OC'ing and other clock stuff is
disabled without doing some nice little modifcations to the board itself.

-Jon

 

[Guest]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

Jonba wrote:

> Hey all-
> I'm running an AMD Athlon Thunderbird, which according to the specs is
> 1.33ghz with a 266mhz FSB on an ASUS a7n66-vm, which supports 200 and 266
> mhz FSB's. Anyway, according to two diagnostic programs, the it's running at
> 1.33ghz like normal, but only 133mhz on the RAM. What's weird is:
> .EVEREST Home Edition says that the CPU is running at 133 on the FSB.

It is. 133 Mhz is the actual frequency of the bus clock. The data bus is
DDR (Double Data Rate) for a data rate 2 times the clock frequency, I.E.
266 MHz. They're the same thing.

The actual 'clock' is what's fed to the processor to generate it's on-die
clock and what the multiplier operates on. I.E. Your 1.33 Gig processor has
a clock multiplier of 10 (10 x 133 MHz = 1.33 GHz)

> .Belarc Advisor says the circuit board supports 133mhz.
> .The ram itself is Elixir, and should run at 333mhz at most.
>
> So what's the deal? I'm not sure if it's always been like this. There's
> nothing in the BIOS to work with because OC'ing and other clock stuff is
> disabled without doing some nice little modifcations to the board itself.

The deal is it's apparently reporting the memory clock frequency, which is
133 MHz just like the processor clock. Which, seeing how the memory is also
DDR, comes to a memory data rate of 266MHz.

 

[Guest]

Archived from groups: alt.comp.hardware.homebuilt (More info?)

On Mon, 02 Aug 2004 04:54:34 GMT, "Jonba" <jon@1000julys.com>
wrote:

>Hey all-
>I'm running an AMD Athlon Thunderbird, which according to the specs is
>1.33ghz with a 266mhz FSB on an ASUS a7n66-vm, which supports 200 and 266
>mhz FSB's. Anyway, according to two diagnostic programs, the it's running at
>1.33ghz like normal, but only 133mhz on the RAM. What's weird is:
>.EVEREST Home Edition says that the CPU is running at 133 on the FSB.
>.Belarc Advisor says the circuit board supports 133mhz.
>.The ram itself is Elixir, and should run at 333mhz at most.
>
>So what's the deal? I'm not sure if it's always been like this. There's
>nothing in the BIOS to work with because OC'ing and other clock stuff is
>disabled without doing some nice little modifcations to the board itself.
>
>-Jon
>


The board is working properly... "200" and "266" MHz are not the
FSB clock's speed but that speed in DDR terms... Double Data
Rate, means 133MHz clock rate X 2 = 266. It would be impossible
to accidentally set it to "133" in DDR terms (66 MHz clock rate)
because the board won't support a setting that low.

To use two memory modules you may need keep FSB near 133MHz, but
if you could use a single 512MB DIMM you'd get a near linear 3D
video performance boost by doing that "nice little modification"
you saw to get the FSB up higher, assuming the mod was the
addition of the jumpers next to AGP slot and that your CPU has
some headroom left to overclock since the board's multiplier
setting, while showing up in BIOS with the jumpers, doesn't work
after power off. The board will reset multiplier to default
value again, which is a problem with that CPU due to it having a
real limit around 1.5GHz, IIRC.. Of course there are other mods
to change that multiplier, those traditionally used for *any*
board with Athlon CPU.