Overclocking with nForce 2

Before looking at the nForce2 Overclocking Concept, here are a few general rules 
that influence every concept.
When overclocking we generally hold a synchronised CPU FSB to RAM FSB Clock 
Speed.  FSB to Memory Clock Ratio: 1 to 1
In the higher Front Side Bus area nForce2 Mainboards partially react sensitively to
synchronised Clock Speed and will run unstable.
When overclocking we don't need additional risks or causes of errors as variables.
We need to limit ourselves to errors that we can evaluate, in case we come across
any.

Asynchronised Clock Speed doesn't make any sense on nForce 2. 
Memory speed below CPU FSB leads even with a 333 Mainboard to errors.
I have tried this in tests and was prompted with a ''Black Screen'' after a start. 
Its not worth the risk of an unstable system.
Memory clock speed above CPU FSB works to a certain extent. I have however not 
tested this over a long period. Generally it is not recommended on nForce 2.
Lets have a look at this purely in the sense of performance: 
A higher RAM FSB only minimally increases system performance. 
The CPU becomes a so called bottleneck and it can't handle the data flow as fast as 
it arrives. At the same time the RAM seldom receives more data than it can handle. 
The CPU Front Side Bus is simply  slower. 
Lets agree to stay with a 1 to 1 ratio with all future concepts.

With overclocking we proceed according to what hardware we possess.
The main principle of increasing the CPU Multiplicator or CPU Front Side Bus step by 
step remains the same. 
A combination of both is also possible so long as it is suitable.

We can possibly take on the Mainboard Chipset and RAM when overclocking.
There are many possible combinations. The best performence is achievable with a 
CPU FSB overclocking on a 1 to 1 ratio with the memory.

Through this the system bandwith increase is far greater as if we were only to work
on the CPU Multiplicator.

1.) CPU: 333FSB, Memory: DDR333, unbranded memory
I have at my disposal a 333 FSB AMD CPU with DDR333 RAM of no name label, 
2nd or. 2rd memory.
The conditions are not exactly appealing. 
The Mainboard FSB could be faster, the CPU should also allow a higher clock speed
via the FSB. With the memory there is not a lot of play and eventually none at all
with a FSB increase. 
With No Name, 2nd od. or 2rd memory blocks I wouldn't expect any overclocking 
capabilities and it is possible that I could cause damage to them with such an 
attempt. 

Here we have the classic case for increasing the CPU Multiplicator. 
A FSB increase doesn't make any sense as the memory would soon bring our
intentions to an end. 

I have to work here with a multi ''Locked'' CPU then I only have the choice of 
attempting  to unlock it by tinkering or to say that this won't work and to leave it.
Overclocking in the above example would only make sense when carried out over
the CPU Multiplicator ratio.

2.) CPU: 333FSB, Memory: DDR333, branded memory
I have here a 333 FSB AMD CPU together with DDR333 RAM, which consists of a 
branded memory block.
The preconditions are now a lot better.
From the basic  principals as above in example 1, the CPU Multiplicator is the key to
where I can try to increase system performance.
A step by step Multiplicator increase until the performance limit of the CPU is 
reached.
With new information regarding how how in MHz the CPU clock speed can be
increased, I can get to work on the CPU Front Side Bus [FSB].
The CPU Multiplicator can be decreased somewhat, and the CPU FSB increased and 
an attempt made to go as high in MHz clock speed as was reached at the first
attempt.
At the same time as the FSB increase the memory will also be overclocked. 
Branded memory usually has a reserve for this. A FSB increase of 10 to 20 higher
as 166 should be available.
We can progress by a RAM vdimm increase in tolerable limits and possibly defuse of
Latency Values, in order to have success. 

3.) CPU: 400FSB, Memory: DDR333 , unbranded memory
Now we have a 400FSB AMD CPU together with DDR333 No Name unbranded, 
2nd or. 2rd memory block  at our disposal.
The preconditions are not necessarily better as in example 2.
It appears as an unlogical mixed combination.  An AMD XP3000+ or 3200+ with 
older one DDR333 memory. The Memory in this case is clearly the weak link which
puts a brake on system performence.
As the CPU already runs on FSB400 the Memory FSB must be raised.
Unfortunately No Name, 2nd or 2rd Memory Blocks won't do us any favours.
The Overclocking tolerance of the RAM stretches only from nothing to little. 
The best intended recommendation would be to purchase DDR400 memory.
If you are able to do this and want to continue with overclocking then take a look 
further at the concept list below.  

4.) CPU: 400FSB, Memory: DDR333 , branded memory
I have here at my disposal a 400FSB AMD CPU together with DDR333 RAM this time
it is branded memory.
The preconditions are no better than in example 3.
As in example 3 we have an unlogical mixture setup. 
As the CPU already runs on FSB400 the Memory FSB must be raised. 
In this example however the RAM will be overclocked. 
A RAM vdimm increase within bearable limits and a possible defuse of the latency 
values will enable us to progress.
More complicated is the question of how to increase the RAM FSB as our CPU already
runs on a 400FSB and the asynchrone clocking should be partially or fully removed.
A well intended recommendation here would be to swap the RAM for DDR400. 
The next possibility would be to clock the RAM using the Memory Frequency Settings
in the BIOS with a % specification of over 100. This would be a delicate matter if we
were to still asynchrone clock.
We would have more hope of sucess if we were to minimally slow down the CPU, 
initially decrease the CPU FSB to 166 in the BIOS and then gradually increase it until
we reach the limit of memory overclocking. 
It is possible that we will only reach a FSB medium in the 180s in the BIOS, however
the system is faster than before.

5.) CPU: 333FSB, Memory: DDR400
We now have a 333 FSB AMD CPU together with DDR400 Memory. 
A mix setup that doesn't really fit well on nForce2 but is however often seen and is
currently around.
This is a combination that frequently appears when Memory has been fitted in
retrospect.
In price there is no real difference between DDR400 RAM and DDR333. 
Memory is upwards compatible, so why not upgrade to DDR400 Memory.
Another reason of purchase,  intention to overclocks the processor. 

The above mentioned system has two positive elements. The mainboard is FSB 400 
capable and the memory is as well. 
Accordingly our strategy can be quickly realised. 
Here the CPU Front Side Bus (FSB) must be increased possibly to 400.
That is BIOS 200 FSB setting.

With an AMD XP2500+, 2600+ we have the best preconditions.
Reason: The CPU Multiplicator lies at 11 or 11.5 respectively and allows the FSB
leeway to be increased. It doesn't really matter whether the CPU Multiplicator is
locked or unlocked.
If need be an AMD XP2600+ which is presenting problems when overclocking shoud 
be decreased in the CPU Multiplicator.
Things look a bit different with a AMD 2800+, 3000+. The CPU Multiplicator 
is already set so high that overclocking via the CPU under certain circumstances
doesn't allow much leeway.
A suggestion with the AMD2800+ was to look how far one could reach in case of
need by decreasing the Multiplicator. 
Starting from a AMD3000+ CCU the multiplicator should be directly changed.
If the CPU is locked it is best to tinker with it to unlock it. 
If you don't wish to use this method you will have to accept only what is on offer
and establish the highest possible FSB with existing Multiplicator.
The CPU Front Side Bus can only be gradually increased. 

6.) CPU: 400FSB, Memory: DDR400 , unbranded memory
Here we have a 400 FSB AMD CPU together with DDR400 unbranded Memory.
This setup makes it difficult to achieve any improvement. 
Because of the relative poor quality of the memory it is as good as impossible to
increase the CPU FSB.
It doesn't matter whether its an AMD XP3000+ or a 3200+ in both cases it is
better to try and increase the CPU Multiplicator even if the gain is only as little 
as 0.5. 
This system does not have much of a reserve in store.

7.) CPU: 400FSB, Memory: DDR400 , branded memory
This system consists of a 400 AMD FSB CPU together with DDR400 RAM which is
a branded block memory.
Our chance to improve this system are better as in example 6 above.
On the one hand there is the possibility of a small increase in the CPU Multiplicator 
but priority should be to try acquire more performence via the FSB. 
This would bring more system bandwidth.
It is advisable to increase the CPU FSB in small steps. The mainboard chipset and 
memory will also be overclocked.
We can  increase the  memory vdimm in tolerable limits and possibly also defuse 
of the Latency Values. A Chipset VDD increase may also come into question.
Decisive for a VDD increase would be how far one could overclock the memory and it
which regions one moves with the Front Side Bus.
After sounding out the maximum Front Side Bus one could try, as  mentioned above
to slightlyincrease the CPU Multiplicator. 

8.) Mobile CPU: 133FSB, Memory: DDR400 , branded memory
This is a classic overclocking system combination, purchased with the intention to 
ooverclock. 
The preconditions here are gut to very good.
The actual Mobile AMD XP CPUs are the types: XP-2400+, 2500+ and 2600+
All of these generally indicate that the CPU Multiplicator is free.
The 2400 series has a T-Bred CPU Core, the 2500+ and the 2600+ have a Barton 
CPU Core. In view of their better CPU Core and higher specification, the Barton Core
CPUs are better suited for overclocking. Additional they have more L2 Cache.
All of the three Mobile XPs are from the start 133 FSB CPUs with an accordingly high
Multiplicator. There are CPUs with 1.45 or 1.65 V. factory default v/cores.
At first glance this would seem to cause concern, a 133 FSB CPU to overclock
up to 200FSB or more ? 
However one can confidently forget these concerns. 
The XP-M2600+ in the 1.45 v/core variant is a pleasure for a Socket A overclocker. 
In quality the 1.45 vcore CPUs are very well produced. After all AMD itself 
guarantees a 1.45 vcore operation with an equal CPU Mhz end output.
As a comparison, the normal default voltage of a XP Barton CPU is 1.65 Volt.
A CPU v/core allows itself to be increased for support. 
Its often the case that nothing more than a normal  vcore of a XP Barton CPU is
necessary for a top overclocking.
Advantage: The CPU doesn't get too warm.
One could also in this case try to pull the CPU over a XP3200+ ranking using 
Multi 11.5 and 12 with the FSB of 200. 
As in example 7 above it is best at first to hold back and to try and achieve more
MHz ouput via the FSB.
So, once more we will try to increase here the FSB in smaller steps.
The mainboard chipset and memory will also be overclocked.
We can  increase the  memory vdimm in tolerable limits and possibly also defuse 
of the Latency Values to overclock the memory.
Decisive for a VDD increase will be how far one can overclock the memory and in 
whichareas we work with the FSB.
After sounding out the maximum Front Side Bus one could try, as mentioned above
to slightly increase the CPU Multiplicator.
In the case of the system posessing so called High End Low Latency RAM then a 
value of over 400 with the FSB could be easier to handle.

9.) CPU XP-M, 333 or 400 FSB, Memory: DDR433 or better 
Likewise this is an overclocking combination. The memory was certainly not 
purchased only to have it running clock of a RAM FSB 400.
The preconditions are very good. We can retrieve the very last FSB reserve capacity
from the CPU and Mainboard. 
As the Mainboard will be performing at this level we need to pay attention to the 
cooling.
The concept here is clear, we must use a higher memory FSB clock. 
It is only worth considering overclocking via the CPU Multiplicator if the system is 
equiped with a FSB4 00 processor and through that an already high CPU Multiplicator
stands in our way when increasing the FSB. 
If this factor comes in question then the CPU Multiplicator will have to be decreased.
Also in this example we will increase the CPU FSB in smaller steps. 
The Mainboard Chipset and memory will be overclocked with it. 
We can  increase the  RAM vdimm in tolerable limits and possibly also defuse the
latency values. A Chipset VDD increase may also come into the calculation.
Decisive for a VDD increase will be how far one can overclock the memory and in 
which areas we work with the FSB.
DDR433 RAM offers, for example, already a guaranteed Memory Bios FSB of 217. 
If one overclocks this RAM a FSB of 235 to 240 could be possible.
A FSB at this level is to all intents and purposes on the nForce2 possible and it is not
an isolated case.
One should generally check whether an optimised overclocker custom BIOS for the 
mainboard is present or not. 
Owners of DFI nForce2 have the best BIOS preconditions already.

Those were my concept recommendations.
Here and there there will be other system preconditions present, eg. a FSB 133 CPU
Unfortunately I can't add all of the variables to the list as it would become never
ending.
However even with a FSB 133 CPU one can find a suitable solution above.

The recommendations are primarily set out that the FSB will be raised as this 
produces better performance and increases bandwidth.
If anyone has a different opinion they are welcome to overclock via the CPU 
Multiplicator, non of the recommendations in the above list are binding regulations.
I present them as I have found them through experience to be sensible options.

Now we can grab the actual overclocking itself and proceed to [Page 3] of the 
nForce2 OC Guide 

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