New OC'er, couple Q's

E

evanisthecoastie

Supreme [H]ardness
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Nov 14, 2006
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As you saw, im brand new to overclocking, very addicting and ive barely even started tweaking! Spent all day yesterday reading about different techniques and such and decided to finally give it a shot, taking it easy and playing it safe so far.

What im using:

ASUS M4A79XTD EVO AM3 AMD 790X

Phenom II X4 965 BE 140W

ZALMAN CNPS9900

PC Power & Cooling Silencer PPCS750QBL 750W

All right, so far all i have messed with is changing the multi and vcore a tad, dont fully understand how to do FSB tweaks yet.

on changing multi by itself i can go 3.6ghz stable prime95 for 3 hours, but anything after that i have to start messing with the voltage. cpuz shows what i think to be MASSIVE fluctuation, which i think is a PS problem. Ive heard my PS is a POS so i might swap it out for something better. temps under full load at 3.6 were around 42 tops. could be better but it ran fine.

I pushed the temps more and changed the multi to 19, which i needed to up to 1.5v, which is where i have some trouble keeping it stable. It will run prime 95 for about 5 mins before bluescreen. now, at this vcore i start to get iffy because most of what i read says to stay in the 1.4 range, is that correct? Im scared to keep upping the voltage because once i hit 1.5 the heat is just too much i think, it pushed the cores to about 56c max, hovering around 54 for the most part. I cant keep it stable at 1.5, should i keep pushing the voltage? In BFBC2 it runs fine, stable for a couple hours, temps around 48 which im comfortable with.

What are the heat tolerances with this chip? Ive googled and find answers all over the place so Im not sure whats safe and whats not. Any tips for what i should start to tweak next being new?

I turned off acc, cool and quiet, and all the normal stuff.

should i change powersupplies? I am quite worried about the voltages being reported by cpuz, i have it set in bios (i do everything in bios FYI) to 1.5, but in cpuz it shows it dropping to around 1.38 under load sometimes! is this normal?
 
not able to help too much, but it is normal for vcore to show as lower in the OS vs BIOS, but I've not seen that much of a difference before. Is it very unstable as it it bounces all over the place? if so, and its worth the cost to you, yea you may look into getting a better PS.

I would think a 1.5vcore is not healthy for long term use. (those are stock at 1.35 right?)

anything lower than 60c should be ok, but not really ideal to be above 50. (just my general knowledge from various cpus, not that one in particular so someone may chime in otherwise.)
 
Just another general question about overclocking. Is it true that overclocking reduces the lifespan of the processor?
 
You shouldn't need that much voltage, I think the problem is most likely northbridge settings (see below). You should also considering posting in the AMD section. With the market the way it is 90% intel/10% AMD, it is harder to get help on AMDs. I think I have ~10 phenom/athlon II boxes on my desk. Would be funny to make an [H] pic if I get more, but the point is I've oc'ed a lot of these.

You won't break it. They are tanks as far as the voltage they can take. Incredible actually. The 955 I am running at right now has been as high as 1.75 for repeated attempts at ~4,500mhz stability.

Overclocking a phenom is different than an i3/i5/i7.

Some pointers:

Some c3 stepping x4 phenoms will do huge megahertz. Most will not, so do not go in expecting this. The most you can reasonably EXPECT is 3.8 on just about any c3 x4. In my experience, x4 phenom IIs hate FSB overclocking and stability is very difficult. Thubans (x6s) are the opposite. So leave that alone.

Phenoms are sensitive to the speed of the northbridge. The northbridge talks to the memory for the cpu, so if it is not fast enough they will "out of sync" so to speak. Even if they do not, the performance will not be as good as if the northbridge was higher.

Most air cooled c3 x4s will tolerate a 2,400-2,500mhz northbridge at most.

Having the northbridge speed and CPU-NB VID will have a greater effect on stability (up until about 3.9 and beyond) than CPU Vcore will.

Throw out your current settings and start with this:

Multiplier: 19 (3,800mhz)
FSB: 200
Hyper Transport Multiplier: 10 (2,000mhz) - do not raise the hyper above 2k
Northbridge Multiplier: 12 (2,400mhz)

CPU Vcore: 1.4v
CPU-NB VID: 1.225

Assuming your chip is an average oc'er, you should have great results with these stats. Also, as long as you are below 60 degrees celsius on your core and TMPIN1 temperatures, it is safe to push the processor right up to those. You won't harm it.
 
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The only reason people call those power supplies a POS is because they had a high failure rate out of the box. If you've used the PSU for a long time, and it's working, it's fine. Don't worry about it. Because, if it works, those PSU's have VERY stable voltage output.

The voltage fluctuation you're seeing is probably due to something most motherboards have--v-droop. To a certain extent, mobos are engineered to allow for v-droop, so as to keep cpu temps down and save wear-and-tear on the CPU's transistor gates. You can overclock with v-droop present. However, maximum overclocking requires disabling v-droop (called by many names depending on the mobo manufactuer). Sometimes there's a setting in the BIOS to do this. Other times, you have to resort to pencil-mods or soldering. Measuring voltages with a multimeter is always more precise than software. But, I'm not sure if your mobo has easy measuring points.

The things you need to worry about most in overclocking is voltage and temperature. Try to keep your CPU below 70C when doing stress testing. LinX is one of my favorite stress apps. For prime95, don't undervalue how your system reacts to small-fft, as this will stress the system differently than blend and large-fft's.

Also, don't forget. Your memory controller is built on the CPU. So when you overclock the CPU, you also overclock the memory controller, which could require you to alter you memory timings, even though you may not be overclocking the memory.
 
@quitesufficient thanks for the tips! gonna try it out right now :) I had no idea the tolerances were so high, this makes me much more comfortable with toying with this sucker!

@ Rock&roll Thanks for the PS knowledge, been using mine for about 2 years+ now so its nice to know i got a good one. ill try the small fft's from now on.
 
Rock&Roll said:
The things you need to worry about most in overclocking is voltage and temperature. Try to keep your CPU below 70C when doing stress testing. LinX is one of my favorite stress apps. For prime95, don't undervalue how your system reacts to small-fft, as this will stress the system differently than blend and large-fft's.
Click to expand...

Phenoms cant go to 70C, they will shut off at a little over 60.

Evan you need to make sure you have Cool'N'Quiet, C1E, and Thermal Management all turned off.
 
ive got them all off :)
fyi, this is a C2 chip, should have mentioned that.

tried your settings above, boots to desktop fine, but prime95 blue screens about 5 seconds in, boosted vcore up to 1.5, idling at 41 right now, too afraid to hit test :-O
 
evanisthecoastie said:
ive got them all off :)
fyi, this is a C2 chip, should have mentioned that.

tried your settings above, boots to desktop fine, but prime95 blue screens about 5 seconds in, boosted vcore up to 1.5, idling at 41 right now, too afraid to hit test :-O
Click to expand...

Ah well, that makes quite a bit of difference. Hopefully you can even exceed 3.5, I had one c2 965 I worked on that couldn't do 3.6 with any combination of settings, fairly aggravating.
 
well, ive done 3.7 stable so far for 3 hours, so i know i can hit that, just lowered it back down to 3.7 to see if its still stable with new settings. failed just now on 3.8 again
 
its amazing how much .05 volts can change temps.

edit: well that failed, trying everything back to stock and slowly upping shit.
 
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ok, i can run BFBC2 at 3.8, i wont dare prime95 it, its sure to fail lol.

is it bad to run an OC that isnt stable on prime95, but works for all my other purposes?
 
Try cutting NB-VID to 1.200, that should lower overall temps, then you may be able to prime 3.8ghz
 
if it's not stable at full load, than it cannot be healthy. In my experience, when you are at that point in the OC (close to an upper limit) apps tend to even go slower as they are getting instruction errors that they'll have to repeat instruction sets. I have no proof, but On my e5200 (before I fried it) when the cpu was at 3.8 it ran but I swear boot took twice as long and app loading was atrocious, but 3.7 was smooth as butter.
 
alright, got some good rest last night, and started again, ripped my whole cpu apart, routed cables for an hour or so, dusted all my parts/case. lol.

started tweaking some more, currently running prime95 at 3.8ghz, highest temp atm is 59.

hope it stays stable!

also re-applied thermal paste, this time with AS ceramique.



edit2: holding strong for 1 hour so far :) temps go from 57-58. I think they would be lower once the ceramique cures, as it is less than 2 hours old now.

edit3: 4 hours strong, id say this is stable :) temps leveled off still at 57 degrees about.
 
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