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January 1, 2007, 1:21 pm
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hello,i have a computer with pentium d 805 2,66@3 ghz..corsair memory
pc 4300 ddr2 533 (3-4-4-8-20),motherboard p5ld2-se with latest
bios,power supply from casing 380w...
4 days ago,i overlocked the processor to 3 ghz (20X150) with fsb 600
and memory clock 300mhz,the i tried to change the fsb to 151 so the
clock was 3,2 but the system just shut down and i reboot the pc and
change the fsb to 150,it said overlocking failed..press f1 to setup
bios...why can't i overlock more?do i need to change the psu?
Sorry for bad english.....
The D 805 does draw a lot of power when overclocked.
There are two rate limiting steps. The Vcore on the motherboard
may not be able to handle the load. You should use a program like
Asus Probe or some other monitoring program, to monitor the value
of Vcore. It could be that Vcore is dropping too much, to handle
the overclock. Your board only has three phase power, so there
will be some limit to the power it can regulate.
The other limit will be the power supply. Your power supply will
have a limited amount of +12V to feed the 2x2 connector that goes
to the motherboard.
To work some examples, start with the data from Intel
The processor draws 95W at from 1.25 to 1.4V, 2.66GHz at FSB533.
Since you did not provide any actual Vcore setting info, I'll use
the info from the Tomshardware article.
Page 20 of the article, claims they reached 3.3GHz without a Vcore change.
This is how you work out the power consumption. If your normal Vcore is
a value of V1, and the required Vcore while overclocking is V2, the
power will be:
F2 V2 x V2
Power (watts) = -- x ------- x 95W
F1 V1 x V1
There can be as much of a power penalty from bumping the Vcore,
as from increasing the frequency. If we assume you did not have
to change Vcore, then the ratio of V2 squared over V1 squared is
just 1, so the voltage doesn't change the power level. And
3.2GHz / 2.66GHz * 95W = 114W. The load on the power supply
via the 2x2 connector would be
Amps = ---- x ---- = 10.55A (assumes a 90% efficient Vcore regulator)
Your system shutting down, can be either the CPU hitting the
THERMTRIP temperature. Or it could be the power supply hitting
its overload level. (It could also be the Vcore regulator going into
latchoff, but I doubt it, as the Vcore onboard is probably rated to
drive a 130W processor.) If you were cranking the Vcore a lot,
to get to your current level of overclock, that won't be helping
matters. You should try to overclock as much as possible, with
the default Vcore, or even try dropping the Vcore a notch and
see how far you can get.
I agree with Paul in respect to the PSU in your case. There are many factors
that may restrict how far you can go. Your PSU may be rated at 380w PEAK,
rather than actual running wattage. Many mid/low range PSU manufacturers do
that. I have a Prescott core EM64T (I 630) and all I can get is about a 20%
overclock from 3.0ghz to 3.6ghz and stay perfectly stable. Raising the Vcore
has no effect whatsoever. I got it to 3.9ghz, but had occasional errors and
raising the Vcore only made it run hotter and didn't help with stability. I
use an OCC modular PSU that has a max (startup) rating at 535w and is rated
at 450w for a normal running value. Other than the PSU, memory, clock
generator, heat and just reaching the max of what your particular processor
will do can be factors. Every processor can be different even when out of
the same batch when it comes to how well it may overclock. Prescott based
processors like mine and yours run hot anyway and can be tough to get more
that 15-20% over stock speeds out of them because heat=instability. Good
luck. And btw, your English is fine.........better than many who have
English as their native tongue.
>> 1,9v,so,should i buy a new psu?i stepped up the memory vcore,and it never
>> cooling freezer 7 pro...
You should keep going, and see where your next limit is.
I gave my information, so you could understand:
1) Why the motherboard is getting hot. The processor draws a lot of power.
Increasing the Vcore increases the power drawn too.
2) What your power supply limit could be. You know how many amps your
power supply is good for. You can use the equation to work out
how much current the processor will draw, for a given overclock.
Running Prime95 (torture test option), will tell you whether the
overclock is stable.
55-58c is not too hot for your particular processor. You may have stabilized
the memory, as Paul said, by that increase. You may even go a bit higher
now, but you are getting pretty close to what that particular processor is
going to do with air cooling. 20-30% over stock speed is considered fairly
good for the Prescott cores. Good luck.
Ed Medlin wrote:
okay,i have reached the limit,i want ask,why can't i change the
multiplier higher?now,the multiplier is 20,i tried to change it with
aibooster,software that came from motherboard cd...to 24 X 135 = 3,2
ghz with fsb 540 and 270 memory clock,with same vcore,but it crash
again so i turned it back to 3ghz
But that is how overclocking works. You do your best, and each processor
is different. The machine I'm typing this on, would only overclock from
2.8GHz to 3.2GHz, and my overclock seems to be limited by my motherboard.
(I can apply all the Vcore I want, and I've basically hit "the wall".)
I thought I would get to 3.5GHz, but it isn't going to happen. My machine
is Prime95 stable, and that is it. I cannot overclock further, unless I
want to make a lot of electrical modifications to my motherboard. A guy
in Japan added a bunch of exotic capacitors of various sorts to his board,
but I know how hard those are to buy, and I'm not going to waste my time
trying. So at some point, you take your "cheap and easy" overclock and
just use it :-)
The multiplier is locked on that processor, so nothing can be done there.
Welcome to the world of overclocking....:-). 3ghz is not a bad overclock. I
would strongly suggest NOT to use aibooster if you are adjusting in the bios
too. I tried using it when I first built this system and it actually caused
crashes. I uninstalled it and just used bios settings. I actually got a much
more stable system that way. I would rather do it in hardware anyway.
Ed Medlin wrote:
Hey Ed,finally i overlocked it through 3,6 ghz....See this link
i forgot to set the ratio between fsb and dram,it was 2:1,now it is
5:3,i run it with fsb 180,bus speed 721 mhz and memori clock 300 mhz
ddr2 600...it stable but when restart it takes 2 second to turn on
again,it wasn't like that,but why does it happen?
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