A8N-E Overclocking

[name]

I post the following for feedback and FYI:

I'm running,

A8N-E
AMD 64 3200
1GB (2x512) Mushkin HP DDR400/PC3200 blue.

I've overclocked with the following settings:

HTT = 250
HTT multiplier = 4 (at 3 the system won't boot)
CPU multiplier = 9 (I've read to stay away from half multipliers,
at 9.5 performance goes way down)
DRAM frequency = 333 (at 400 system won't boot)
Memory Timings = at "1T, Auto" or "1T, 2,2,3,5" give similar
benchmarks.

Benchmarks are as follows:

Aida = memory: read 6317MBs/write 2607MBs
Sandra = memory : ran int 3985MBs/ram float 4042MBs

Readouts from Win utilities are as follows:

clockgen - CPU = 2500, HTT = 250, Memory = 208.33, PCI-E = 100, PCI =
33.24
cpuz - corespeed = 2500, multiplier = 10, HTT = 250, Memory = 208


My questions are does the above seem like a reasonable overclock, or am I
missing something, and can anyone think of anyway to get the DRAM to 400?

 

[Ben Pope]

I post the following for feedback and FYI:

I'm running,

A8N-E
AMD 64 3200
1GB (2x512) Mushkin HP DDR400/PC3200 blue.

I've overclocked with the following settings:

HTT = 250
HTT multiplier = 4 (at 3 the system won't boot)
CPU multiplier = 9 (I've read to stay away from half multipliers,
at 9.5 performance goes way down)
DRAM frequency = 333 (at 400 system won't boot)
Memory Timings = at "1T, Auto" or "1T, 2,2,3,5" give similar
benchmarks.

Benchmarks are as follows:

Aida = memory: read 6317MBs/write 2607MBs
Sandra = memory : ran int 3985MBs/ram float 4042MBs

Readouts from Win utilities are as follows:

clockgen - CPU = 2500, HTT = 250, Memory = 208.33, PCI-E = 100, PCI =
33.24
cpuz - corespeed = 2500, multiplier = 10, HTT = 250, Memory = 208


My questions are does the above seem like a reasonable overclock, or am I
missing something, and can anyone think of anyway to get the DRAM to 400?

Something is a bit strange.

Look at the speed of your RAM as reported - 208.33MHz.

Which, when multiplier by the multiplier of 9 has to be 2500MHz, the speed of your CPU.

That has to be about right, looking at the bandwidth from Aida.

Ben

 

[name]

Something is a bit strange.

Look at the speed of your RAM as reported - 208.33MHz.

Which, when multiplier by the multiplier of 9 has to be 2500MHz, the speed
of your CPU.

That has to be about right, looking at the bandwidth from Aida.

Ben

I'm knew to this, so please explain what seems a bit strange. Is the RAM at
208.33MHz too low, too high?

TIA,
john

 

[Paul]

I'm knew to this, so please explain what seems a bit strange. Is the RAM at
208.33MHz too low, too high?

TIA,
john

I think 208.33 is the memory clock fed to your DIMMs. With DDR
(double data rate), there are two transfers per clock cycle.
What Ben has noticed, is you selected "DDR333" in the BIOS,
and yet clock gen sees 208.33 * 2 = DDR416! That means in fact
your RAM is already zipping along. Dual channel DDR400 rates
would give 6400MB/sec (as a DIMM is 8 bytes wide, two DIMMs
are 16 bytes wide, 400*16 = 6400MB/sec), and Aida is showing
6317. To be more exact, at 208.33, your theoretical memory
bandwidth is 6666.56MB/sec, and the 6317 value would be
about 95% efficient.

As for what happened to the memory, remember that when you
lift the HTT frequency, it scales the memory readings too.
That means as a user, you will have to turn down the memory
setting if you happen to lift the HTT any further.

You went from a 200MHz clock for HTT to 250MHz. That is 25%
faster. Your choice of memory clock 333 * 1.25 = DDR416, and
lo and behold, that is what the BIOS gave you.

This means, in the usual Asus style (like on my P4C800-E),
that the memory setting reflects how things would work if
the FSB was at its normal 200MHz.

For example, assuming a normal FSB clock of 200, and your
choice of the x10 multiplier, 200*10/12 = 166MHz , and
with DDR that is DDR333. Asus kept the 12 divider for the
memory, even though you raised the FSB to 250. 250*10/12=208.33,
giving DDR416. It just means the BIOS is too stupid to notice
that the FSB is higher than nominal, which means you'll have
to turn down the memory a corresponding amount. If you raise
the FSB by 25%, turn down the memory by 25%, and so on.

HTH,
Paul

 

[name]

I think 208.33 is the memory clock fed to your DIMMs. With DDR
(double data rate), there are two transfers per clock cycle.
What Ben has noticed, is you selected "DDR333" in the BIOS,
and yet clock gen sees 208.33 * 2 = DDR416! That means in fact
your RAM is already zipping along. Dual channel DDR400 rates
would give 6400MB/sec (as a DIMM is 8 bytes wide, two DIMMs
are 16 bytes wide, 400*16 = 6400MB/sec), and Aida is showing
6317. To be more exact, at 208.33, your theoretical memory
bandwidth is 6666.56MB/sec, and the 6317 value would be
about 95% efficient.

As for what happened to the memory, remember that when you
lift the HTT frequency, it scales the memory readings too.
That means as a user, you will have to turn down the memory
setting if you happen to lift the HTT any further.

You went from a 200MHz clock for HTT to 250MHz. That is 25%
faster. Your choice of memory clock 333 * 1.25 = DDR416, and
lo and behold, that is what the BIOS gave you.

This means, in the usual Asus style (like on my P4C800-E),
that the memory setting reflects how things would work if
the FSB was at its normal 200MHz.

For example, assuming a normal FSB clock of 200, and your
choice of the x10 multiplier, 200*10/12 = 166MHz , and
with DDR that is DDR333. Asus kept the 12 divider for the
memory, even though you raised the FSB to 250. 250*10/12=208.33,
giving DDR416. It just means the BIOS is too stupid to notice
that the FSB is higher than nominal, which means you'll have
to turn down the memory a corresponding amount. If you raise
the FSB by 25%, turn down the memory by 25%, and so on.

HTH,
Paul

I'm beginning to understand and now, at least, I know what I don't know. I
don't understand how the divider is calcuted. I understand that if you have
DDR400 it means that it's actually running 200 once on the rise and once on
the fall of the clock cycle and that the divider is then1:1. Similarly 333
runs 166 on the rise and fall, but what's the divider? When you say Asus
kept the 12 divider what does the 12 divider actually mean and how is it
calculated. I understand it place in the equation to determine the mem
freq, in your example, 250*10/12=208.33. And that's another thing, where's
the 10 multiplier come from, I'm using a 9 cpu multi? Please help with
this, I'm really trying to understand.

john

 

[Ben Pope]

I'm beginning to understand and now, at least, I know what I don't know. I
don't understand how the divider is calcuted. I understand that if you have
DDR400 it means that it's actually running 200 once on the rise and once on
the fall of the clock cycle and that the divider is then1:1. Similarly 333
runs 166 on the rise and fall, but what's the divider? When you say Asus
kept the 12 divider what does the 12 divider actually mean and how is it
calculated. I understand it place in the equation to determine the mem
freq, in your example, 250*10/12=208.33. And that's another thing, where's
the 10 multiplier come from, I'm using a 9 cpu multi? Please help with
this, I'm really trying to understand.

You may have selected 9, but your CPU has a multiplier of 10 by default (I think), and I believe thats whats being used.

So your HTT is 250MHz, a 25% overclock.

Your multiplier is 10, giving you 2500MHz.

200MHz is the default speed of HTT, so when you set your RAM to 167MHz (333) thats 167MHz/200MHz = 0.833 = 10/12.

But HTT is 250MHz, not 200MHz, and since your RAM is on a multipler to your HTT (not fixed to a speed, as it suggests), thats actually 167MHz * 250MHz/200MHz = 208MHz.

Does that make sense? Essentially the RAM is at a fixed multiple of HTT, not a frequency. And your CPU multiplier is 10 (not 9).

Bascially, completely ignore your BIOS, ok?

Actually I think I have learnt why my (VERY brief) overclock attempts failed miserably on my MSI K8N Diamond, I think it does the same thing.

Ben

 

[name]

You may have selected 9, but your CPU has a multiplier of 10 by default (I
think), and I believe thats whats being used.

So your HTT is 250MHz, a 25% overclock.

Your multiplier is 10, giving you 2500MHz.

200MHz is the default speed of HTT, so when you set your RAM to 167MHz
(333) thats 167MHz/200MHz = 0.833 = 10/12.

But HTT is 250MHz, not 200MHz, and since your RAM is on a multipler to
your HTT (not fixed to a speed, as it suggests), thats actually 167MHz *
250MHz/200MHz = 208MHz.

Does that make sense? Essentially the RAM is at a fixed multiple of HTT,
not a frequency. And your CPU multiplier is 10 (not 9).

Bascially, completely ignore your BIOS, ok?

Actually I think I have learnt why my (VERY brief) overclock attempts
failed miserably on my MSI K8N Diamond, I think it does the same thing.

Ben

Thank you so much, you're explanation is very clear, and now I understand.
And, BTW, I had a corrupt BIOS which is why even I set the cpu multi to 9 is
was still 10. Once I flashed the new BIOS and set the CPU multi to 9 that's
exactly what cpuz and CPUMSR showed.

john

 

[Ed]

Don't know if this helps u any but FWIW....
Study of Athlon 64 Overclocking Techniques
http://www.neoseeker.com/Articles/Hardware/Guides/athlon64oc/index.html

Cheers,
Ed

 

[name]

Thanks, I've already checked this out.

john