Bob said:
Thanks for the ADVERTISEMENT
OK, anyone want to help me with my original post?
or am I on the "blacklist" already?
Really, it is a question of how many times we type up the same answer.
************ Orig question ***********
Motherboard= Asus A8S-X
Chipset SiS 756, AMD Hammer
CPU AMD Athlon 64 3500+ Venice S939 Step DH-E6
RAM 1024 MB (PC3200 DDR SDRAM) Corsair VS1GB400C3
RAM TIMING IS CURRENTLY 3-3-3-8
1. CAN THIS BE TWEAKED/OVERCLOCKED?
2. HOW DO I OVERCLOCK/TWEAK, DO I USE A PROGRAM OR IS THIS DONE IN
BIOS?
3. WHAT BENEFITS WOULD I SEE?
4. WHAT IS A GOOD METHOD TO TEST THE TWEAK/OC FOR STABILITY?
sorry for the caps-lock
Maybe someone could give me a url if the answer is too long or
detailed?
thanks a billion!
***************************************
1. Yes
2. BIOS, or A64Tweaker, or Clockgen if it knew about your clock chip
3. 2% via memory overclocking alone. Core overclock is more effective.
http://www.xbitlabs.com/articles/cpu/print/athlon64-e3-mem.html
4. Memtest86+, Knoppix LiveCD + Prime95, Windows + Prime95
OK, I have a copy of the the original A8S-X manual (there is A8S-X and
A8S-X SE).
First of all, the main clock feeds the CPU, and the assumption in the
manual, is that the clock = 200MHz. Many of the settings in the BIOS
are based on integer ratios. And when a BIOS setting says something about
MHz, the thing it is actually adjusting is some integer setting in a
register somewhere, for a multiplier or divider circuit.
1) Set "AI Overclocking" to [Manual]
The "CPU Frequency" [XXX] menu item appears.
By default it should read 200MHz. This is the main clock.
This is how you overclock.
2) Find the section in the manual called "HyperTransport Configuration".
"Hypertransport Speed" offers values like [800MHz] and [1000MHz].
These values are in fact, just multipliers. The multiplier value,
takes the main clock as an input, and multiplies by an integer
value. If I select [800MHz] in the BIOS, I am selecting a HyperTransport
multipler of 4x. The HyperTransport bus has a max speed, like 1000MHz.
If I want to overclock my board, I have to reduce the HyperTransport
multiplier, so the HyperTransport bus doesn't run too fast by accident.
Example. Set "HyperTransport Speed" for a 4x multiplier. If I raise
the main clock to 250MHz, the new HyperTransport bus speed is
250MHz*4 = 1000MHz and just barely in spec. If I only raised the
main clock to 233MHz, 233MHz*4=932MHz, which is less than 1000 and
is in spec. So crank the HyperTransport Speed down, to leave room for
overclocking. A choice of [800MHz] means [4x]. A choice of [800MHz]
leaves room for a 25% overclock of the core.
3) Next comes the memory. Now this is pretty complicated stuff, and your
BIOS, at least according to the manual, doesn't show all possible settings.
The memory speed in the BIOS is an "objective", and the processor has
a big table of values inside it. The processor is responsible for using
a clock that won't cause the memory to run too fast, based on the "objective"
set in the BIOS. In your manual, it says to set "Memclock Mode" to [Limit]
and then a "Memclock Value" item appears in the BIOS. If you want to
prevent the memory from limiting your overclocking, simply turn it down.
The manual lists four objectives of [100, 133, 166, 200]. On a revision E
processor, there might be as many as twelve different objective values,
and maybe the latest BIOS for your board, does a better job than the
Asus user manual implies.
http://math.gogar.com/athlon64.cgi?showtable=1
As a simplified example, say I turn the Memclock value down from 200 to
166. My plan is to raise the main clock from 200 to 250MHz, a 25% overclock
of the core. My memory would run at 250 * (166/200) = 207.5MHz or DDR415.
That is actually faster than DDR400, and is slightly above the spec for
your memory (should not be a problem). If you further dropped the Memclock
value to 133, that would give 250 * (133/200) = 166MHz or DDR333, and less
than the DDR400 the memory is capable of (in spec).
So with the HyperTransport turned down, and the Memclock ratio turned down,
you can increase the main clock. Use CPUZ from cpuid.com, in Windows, to
verify what has happed to your clock values, for the various subsystems.
That will help you learn what has just happened to your system. Try a small
change, from 200 to 205, so you can safely boot into Windows and use CPUZ.
For serious overclocks, you'll probably want to boot something other than
your Windows main boot disk.
One thing I've missed out on entirely, is the multiplier used by your
CPU. Your core is 2200MHz, implying the core multiplier is 200 x 11. I
believe you may have an option to turn that down. Turning down your
core multiplier would be used, if you were aiming for a higher memory
clock. (I.e. Light CPU overclock, heavy memory overclock.) In your
manual, the "Processor Frequency Multiplier" will list the allowed
values for your processor. You would only turn this down, if wanting
to really crank the hell out of the memory. And your memory is pretty
ordinary stuff, not some low CAS DDR600 miracle memory.
In the CPU, the Memclock is actually set by a ratio of two numbers, and
the math.gogar.com table above shows the values being used. The table of
values is, as far as I know, stored in the processor's logic (hardwired)
and the entry selected in the table, is based on the settings being used
for your setup. Since the generating equation for the table, uses the
ceiling() function, it means an odd or even Processor Frequency Multiplier
plays a part in the clock used for the memory.
The Gogar site also has an Optimizer, with suggested settings to get to a
particular objective (like heavy CPU overclock, light memory overclock).
Since there are multiple combinations of settings that can give the same
kinds of results, the optimizer shows results according to a weighting the
user provides.
http://math.gogar.com/athlon64.cgi
In these returned results, the first column "HTT" is the "Main Clock" choice.
The first line suggests a value of 250MHz. I'm supposed to use a Processor
Frequency Multiplier of 10x. My core frequency becomes 2500, which is
higher than the normal 11 x 200 used at stock. I'm supposed to set my
memory limit to [200], and it ends up running at DDR500. Since I turned down
my Hypertransport multiplier to 4x, the Hypertransport bus ends up at 1000
(the limit).
HTT CPU Memory Hypertransport (var)
250 10 x 250 = 2500 1:1, 200, DDR400 = 250 (DDR500) 4x250 = 1000 0
250 10 x 250 = 2500 13:12,216,DDR433 = 250 (DDR500) 4x250 = 1000 0
294 8.5 x 294 = 2499 11:12,183,DDR366 = 249.9(DDR500) 3x294 = 882 0.0016
In the second line in the table, the problem would be, your BIOS doesn't
offer [216] for the Memclock Value. At least the manual doesn't list that
as a possible value.
The thing I labelled as "var" in the rightmost column, is a measure of the
deviation from the objectives. A value of 0 means the settings fully meet
my expectations. As the value of "var" gets higher, I'm getting further
away from my expected values (i.e. heavy CPU overclock, light memory
overclock, or whatever).
*****
Here is another site with overclocking instructions. I don't know if this
site just copied someone else's content, or the author wrote this himself.
http://eclipseoc.com/index.php?id=6,9,0,0,1,0
Have fun,
Paul
