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Please advise 1st OC 3.0 Northwood system - Page 3

post #21 of 26
You have been told to look to both the cooling and PSU and have discounted both with a continuation of your problem.

There is a condition called "Threshold Voltage" which is the amount of power necessary to turn on and switch the transistors gates.

There is a formula for the switching power:

Power ~ ½ CV ² Af

This formula states that dissipated power is linear with the effective capacitance, activity and frequency. Power increases quadratically with the CPU's core voltage. Thus when you overclock you are increasing the necessary voltage by a multiple of four, not one for one and it is necessary for a strongly functioning power to supply these needs.

Now leakage power is a fundamental sieve with relation to dynamic power because the leakage power increases exponentially not linearly. Remember when you watered the lawn and there were tiny holes in the water hose? How they somehow got bigger as time went on? Of course the bigger the hole the more water you lose. This is how leakage power works and is part of a current so one (at this time of technology) can not fundamentally stop the leakage, one can only hold it in some form of abeyance.

Then added to the power loss (and hence more power of necessity) there is an added effect called "Wire Delay" which is the effect of the switching speeds and the resistance of the capacitors (RC). Now as you pump up the voltage the RC becomes more of a power bottleneck and thus needs more voltage for the signal to travel.

Thus the amount of power needed to overclock is phenominally higher than a 1:1 ratio. Look to your PSU. Test with a better one rather than discounting the information.


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post #22 of 26
Thread Starter 
Ropey--

I have indeed discounted the cooling because, as I said, since cleaning mine I am experiencing acceptable heat levels idle/load. I have not however discounted the PSU. In fact, I believe my problem must be either that I've reached the limit on my CPU OR that I'm maxing out my PSU. Since others seem to routinely speak of putting more than 1.6 to their chip I assume that is part of the problem. So you see, rather than discounting this excellent advice from the forum, I agree with it. I'm just not ready to go out and buy a new PSU.

Quite honestly, I may differ in attitude from many on this forum--I'm not out to break any records. I just want to get the most out of my existing system without investing any more than necessary into it. If I really wanted to do this, I would go out and buy new DDR500 memory, a (water) cooler, and a new PSU. I just bought a 7800 AGP card, so maybe instead I should have gotten a new mobo with PCI express ... well, if I'm into gaming I guess I should just toss it all aside since everyone seems to know that AMD is the way to go for gamerz... <let me catch my breath here>

No, I made the decision to get the most out of my existing system--the latest vid card and another 512 of RAM--and to see what extra clock cycles I can squeeze out and just leave it at that. If it ends up being 3.5Ghz, well, that's pretty decent. I expect that in about two years I'll be rebuilding everything with 64bit, directx 10 (or 11?), Vista, etc. You see where I'm going with this.

This has been so far a productive and entertaining project for me, and the advice I've gotten here shows that many of you really know your stuff. Though I've been well-employed for the last 7 years as a 2nd & 3rd level PC support tech, I clearly have much still to learn and I appreciate all of the excellent advice (in case I haven't said that enough!) I just don't want anyone to think that I'm being hard-headed just because part the goal of my project is getting more performance for free.
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post #23 of 26
Quote:
Originally Posted by Tonic5
So you see, rather than discounting this excellent advice from the forum, I agree with it. I'm just not ready to go out and buy a new PSU.

I just don't want anyone to think that I'm being hard-headed just because part the goal of my project is getting more performance for free.
Fair enough. We just think differently and that is allright.

Remember though, that the heat levels are not just at idle and load. You will find that the drop from a higher level to a lower level (degree of declination) is far greater on the stock cooling than on an aftermarket cooler. Now when one looks at the price of an aftermarket cooler it is not a great extension to see that price/performance is a net gain. 18A on a 12V Rail is minimal when overclocking and is (I believe) the prime error in your overclock. Remember also that leakage increases with time and that the increase is not due to heat output but rather to electrostatic migration which, when an underpowered PSU is attempting to maintain acceptable levels exacerbates the level spike issuance.

Since you do not wish to spend any money then yes, be happy with what overclock you are able to achieve.

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post #24 of 26
My system is quite similar to yours (see sig), and I easily run on 3.6 GHz, without any increase in voltage, and RAM on 1:1. Like you, I am not out to break records, and I an happy with 3.6 (if time, I might push a bit more), and my temps are 38-40 idle, and 48-49 load, with case fans at lowest speed to keep things quiet.

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post #25 of 26
Thread Starter 
Chozart--

Just read your post. What is your vcore and what are your memory settings? I can't get 1:1 past 3.5. I have set my timings manually to 3/4/4/8, with auto DRAM idle/refresh. the DRAM frequency is 400, and I have tried every voltage combo including AUTO. I can get to 3.6 if I go DRAM=320 instead of 400. Though that brings it close to its original spec, 190~ it's not 1:1.
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post #26 of 26
I tried both 20% and manual. If I hit 20%, vCore = 1.6V. RAM settings 1:1 @ timings 2.5/3/3/8

Manually, I increased the FSB to 240MHz, vCore 1.525V, RAM settings 1:1 @ timings 2.5/3/3/8

See CPUz validation:
http://valid.x86-secret.com/show_oc?id=86193

The RAM is officially rated at timings of 3/3/3/8, so I guess I am lucky to be able to get 2.5.

Seems like the PSU might have to do with it. You know what your volts are? My 12V rail is rock solid at 11.98V, while the 5 volt is 4.94V and the 3 volt 3.31V.

Also, do I see correctly you have four hard drives attached to that PSU, two of which are 10K RPM SCSI? Those will take probably more than 25% (if not 30%) of the available power on the 12V line while booting up (of course drawing less while the system is running, but still drawing a good bit of power).

Good luck.. Let me know if you need more help.
    
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