p4 3gig p4c800 c/clock help

G

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Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

Hi all

New to o/clocking ,
can manage 10% o/clock on p4 3gig p4c800
but anymore causes system to hang,
would passive heatsinks on chipset and better cooling
on cpu temps help?

btw cpu is currently 48c

thx nige.
 

Paul

Splendid
Mar 30, 2004
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Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <ckf70r$3ap$1@sparta.btinternet.com>, "Nige"
<nnnppn@btinternet.com> wrote:

> Hi all
>
> New to o/clocking ,
> can manage 10% o/clock on p4 3gig p4c800
> but anymore causes system to hang,
> would passive heatsinks on chipset and better cooling
> on cpu temps help?
>
> btw cpu is currently 48c
>
> thx nige.

Well, the person answering your question could write a book.

Overclocking starts well before you've bought components. You
need the right mix of components, and an understanding of what
frequencies you are going to use, to put the project on a solid
footing. Since the P4 is multiplier locked, you have the normal
FSB and the overclocked value of FSB to consider, then find the
right RAM to cover those two FSB choices. You've started
at 3GHz, you don't have too far to go, before the processor will
be reaching its limits. You can check out those limits here:

http://www.cpudatabase.com/CPUdb

It looks like a Prescott 3.0GHz is good for 3.7GHz on air, and
a Northwood 3.0GHz is good for maybe 3.8GHz on air. That means
the CPU clock will go from 200MHz to 250MHz. At 1:1 CPU:Mem
ratio, that requires DDR500 memory, and at 5:4 CPU:Mem ratio,
that only requires DDR400 (PC3200) memory.

You haven't given details about your RAM, so it is hard to
be more specific.

A true overclocker wouldn't worry about the amount of RAM needed
to do normal work on the computer. A true overclocker would use
2x256MB single sided DIMMs, in dual channel mode, to achieve the
highest possible DDR speed from the memory subsystem. But, perhaps,
512MB might not be enough for all gaming applications, so if your
objective was fast gaming, then you may not be able to run quite
as fast a memory subsystem. If you want more ram than that, 2x512MB
is still possible, but may not go quite as high, and if you want
say 4x512MB double sided, then maybe DDR440 is the limit. (I
still haven't seen the results of any 2x1GB module experiments,
with the Corsair modules for example, so don't know if they are
better than some Samsung rev. F TCCD or Micron CAS2 chips in a
4x512MB configuration.)

A minor consideration is whether PAT is enabled or not. That will
give a slight boost in memory bandwidth, but not all combinations
of RAM and FSB allow it to engage. There is a small book written
on that topic alone.

In any case, given all the right ingredients, an overclocker would
never use the BIOS AI feature for overclocking. You should be setting
FSB, memory timings, CPU:Mem ratio, Vcore, Vdimm manually, to get
the best settings for your hardware. You will also need the right
software setup for testing, as if you overclock and boot Windows in
an unstable state, you can bork the install. I'm new at this stuff,
and I disconnect the hard drive and only have CDROM and floppy
connected. I've got a Knoppix read-only Linux CDROM to boot the
computer, and I have a copy of Prime95 on a floppy, for testing
system integrity when overclocking. Knoppix even has a boot option
to run memtest86, right from the boot prompt, so you don't even need
to visit memtest.org, to have a memory test program. You can even
surf and read newsgroups while running your Prime95 testing, so you
get to do some things with the machine, while checking for integrity.

If you want to check system temps, there is xmbmon for Linux. That
will access the hardware monitor chip, and give raw readings from the
hardware. It is good enough for determining whether you are
overheating or not. And for a guy like me, simpler to set up than
lmsensors.

So, the best advice, is to use manual settings, but first understanding
whether you've got good RAM for the job or not. It doesn't even
need tight timings, but the ability to handle a fast memory clock
will help a lot. DDR500 3-4-4-8 should give excellent results, if
running two sticks.

As far as temps go, a Prescott will thermal throttle at 70C, so
that is one temperature to avoid, if you are benchmarking. If 48C
is your idle temperature, then I'd probably want a better HSF for
the CPU. If 48C is at 100% load, then you are probably OK for now.

As for the Northbridge, it has a power dissipation rating of maybe
10 watts, under some conditions. But, I wouldn't expect every
Northbridge to be doing that. The Northbridge gets a bit more
stress when it is overclocked, but as the power equation is FCV**2,
if you are using Winbond BH-5 memories, and running a Vdimm mod
for 3.1 volts or so, then you would want to consider putting a
fan on it. I think I looked up the max temp for the Northbridge
a while back, and it is something like 99C or so. Depending on
the heatsink fan you have on the CPU, you may get enough
"air spill" from the CPU cooling, to keep the Northbridge happy.
Feeling the heatsink with your finger should give you a good
idea of how stressed it is - if you cannot hold your finger on
the heatsink for more than 2 seconds, then the heatsink is at
55C, and the die will be at around 80-85C or so (wild ass guesses).
(I've had an 865G Northbridge heatsink run at 75C, as measured
by a digital thermometer, and it ran without complaining, so
they seem to be able to take a bit of heat.)

On the topic of Vdimm, for all those crazies out there using
the OCZ Vdimm booster - check the datasheet for the hardware
you are using. For example, I looked up the VDD_IO for an
Athlon64 socket939, and absolute max is 2.9V. A person boosting
a Socket939 board to 3.1V to run their BH-5 memory, is playing
with dynamite, and can easily kill a very expensive processor.
Most people only think about the ram being stressed, but the
Northbridge on a P4 system also gets that voltage, and the
memory controller inside an Athlon64 also gets that voltage,
so before doing a volt mod, the limits of the other hardware
have to be considered too.

HTH,
Paul