Posting my question as Rob suggested I do :)

M

Mysticode

Obliviot
Don't laugh, I still have a Core 2 Duo E4300. I have had it OC'd to 330 FSB with the default 9x multiplier, and everything else on auto. Asus P5B Deluxe motherboard.

Recently, I've had some instability, not sure too why. Ran Prime 95 version 26, and I noticed CPU 1 (core 1) failed after a few minutes with a "Rounding error. 0.5 expected 0.6..". CPU 2 (core 2?) keeps running for hours without a problem.

My vcore is on auto, and is currently running @ 1.376 at load (playing WoW as I type this).

Any ideas? Will be upgrading most likely near to Christmas, but I'd like to stabilize things as best as possible in the mean time, without getting rid of my overclock.
 
Tharic-Nar

Tharic-Nar

Senior Editor
Staff member
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With the FSB clocked up, what's your memory working at? Could be a mem issue, rather than CPU. Full OC details and system specs will help.

- and welcome to the forums. :)
 
Tharic-Nar

Tharic-Nar

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Staff member
Moderator
With mem set to auto, it's likely scaling with the FSB, which means it could be working harder than it should. See if you can set it to a fixed speed or lower the ratio. Without knowing the mem type and speed, it's a little hard to say. Even some relaxed CAS timings or voltage bump might help.
 
M

Mysticode

Obliviot
I've lost track of the timings, but here are the model numbers:

2 sticks of OCZ "OCZ2N10661G" (total of 2GB)

Later also added.. 2 sticks of Corsair "CM2X1024-6400C4" (another 2GB)

I am 95% sure that the OCZ ram is 5-5-5-15, and the Corsair is 5-5-5-18, but I might be wrong. With those timings, the best I could do with those sticks combined is 5-5-5-18, correct?

If my FSB is at 300, I'd want to set my memory to be running at 600 (give or take) to be a 1:1 match to the FSB, correct?
 
Tharic-Nar

Tharic-Nar

Senior Editor
Staff member
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Mixed memory, ah... ok.

The OCZ RAM will can run at 1066, while the Corsair RAM will run at 800. Memory should be set to the lowest common denominator, in this case, 800. Same goes for the timings. Since the corsair set has a lower speed, it can have tighter timings, 4-4-4-12 i think. I don't know if the OCZ set could run at 800 with the same timings though. But to be safe, you may want to set both to 800 and 5-5-5-15. Both will run at 2.1v though, so you should be ok there.

With RAM set slower than normal, test stability again, then we can work on the CPU.
 
Tharic-Nar

Tharic-Nar

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It will treat them all the same (part of the problem of mixed RAM). You have to treat them all the same, thus set all to the lowest common level.
 
Tharic-Nar

Tharic-Nar

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The Corsair RAM should be able to do 4-4-4-12 at 800 according to its specs, which is faster. So we'll go with the slower timings of the OCZ instead. but since this is a test, you can go with 5-5-5-18 if you wish, it won't cause a massive issue.
 
M

Mysticode

Obliviot
Gotcha. Let me just figure this out for my own sanity. 4-4-4-12 is "tighter" timings than 5-5-5-12 (OCZ speed), correct? If this is true, I would imagine I could only set my ram to be 5-5-5-12, which is what the OCZ is marked it can go to. If i go to 4-4-4-12, I wouldn't think my OCZ ram would be able to match the speed.

Also, the 5-5-5-18 was a typo above.
 
Tharic-Nar

Tharic-Nar

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This is part of the complication (and the headache that mixed memory brings to the equation). Timings are latency, the delay between actions, thus, high numbers equal more time, thus slower. Frequency is the operational clock speed of the RAM, thus higher equal faster, since it can do more in the same time.

The OCZ RAM has a higher frequency, but due to internal stress, it has to increase the latency between actions (increase timings). If the RAM were set to a lower frequency (800), it may be able to achieve the same timings as the Corsair RAM, but without knowing for sure, it's best not to risk it.

By setting the frequency lower and the timings higher, you're making sure the RAM runs slower, thus reducing its stress. This means that if you still have problems with your OC, then they will be purely CPU and/or FSB based.
 
M

Mysticode

Obliviot
So with all of that said, the "higher" timings would be the 5-5-5-12 that the OCZ is spec'd at, correct?

Also, the RAM's frequency would be the 1:1 setting, which is my 330 FB x2, being a 660 mhz frequency? Far below 800.
 
Tharic-Nar

Tharic-Nar

Senior Editor
Staff member
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Yes

If memory serves, it has a ratio strap, based on bus speed. As you increase the FSB, it changes the strap too (internally), which is a north bridge setting I think. You might be able to get away with 4:5. But for the time being, you can keep it in a slow mem speed for compatibility sake as you stress test the CPU. Once you have the CPU stable, you can then increase the ratio and/or decrease the timings. At that point, it can get tricky, so be sure to make notes on changes.
 
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M

Mysticode

Obliviot
Yeah it's pretty neat how it does have that ratio strap, makes things a tad easier.

So my plan is to keep the 1:1, and get the timings sitting at 5-5-5-12. Anything I should do for voltage? That was my primary concern.
 
Tharic-Nar

Tharic-Nar

Senior Editor
Staff member
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The RAM will work at 2.1v - if not, it's got issues... or there be a ratio problem with the strap. FSB based OC'ing gets very complicated very quickly when you don't have a CPU multiplier to play with. If you still have problems, you may want to do a complete stock reset and test for stability that way, making sure that the RAM is set slow. If you still get problems, there's a chance of bad RAM - often brought about by long term OC.

With CPU voltage, i think you're safe up to about 1.456v, most tend not go over 1.5. If this is an OC that has been running a long time, don't be too surprised to see instability now. Up the voltage a bit and check if you want, but otherwise, pull back on the FSB.
 
M

Mysticode

Obliviot
I won't touch the RAM's voltage, never have, so I won't start now.

For core voltage, if CPU-Z is reporting 1.376 at load, is it ok to pump it up further? Currently running at 2969.9MHz, 330MHz FSB.
 
Psi*

Psi*

Tech Monkey
How long has the system been running?

Dust accumulates in the fins of the heat sink reducing efficiency with consequential rise in CPU temp. Verify with a utility to see what the cores are running at. It is not unusual for cores to be at different temps no matter what is done with the heatsink or thermal compound.

Plan on removing the heatsink to be able to clean it well.
 
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