Some help needed with OC i5 3470k

drulia

drulia

drulia

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5 Apr 2013
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Just started to play with OC, have basically no previous experience. I have i5 3470k CPU and Asus P8Z77-V LX Intel Z77 mobo.

I changed multiplier to 42, now it runs at max 4200 MHz, I updated the voltage to -0.005, because if I leave it on Auto, voltage goes up to 1.35 when running full load, and 0.000 changes automatically to Auto. With -0.005 I reach 1.256 core voltage once windows just loaded and still starting services. Testing with prime95 for max heat it reaches 1.2 with temperatures up to 71C on full load. I'm quite happy with everything just wondering if voltage is good, not too high?

Also there seems to be weird issue with not showing bios screen on start, going straight to windows, not always, but when it happens I have no mouse control until it loads into windows 8 cover and then I have to click some button on keyboard to remove screen cover and only then my mouse appears, while usually if bios screen shows at start, my mouse is available at the OS choose window. I have Ubuntu installed as well. I have also tried to keep clicking delete button constantly while starting pc, and that doesn't help as well.

UPDATE
Also there seem to be different number of voltage in CPU-Z and Core Temp programs, while CPU-Z shows up to 1.256, Core Temp VID field shows up to 1.31, which one I should believe?
 
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What does your BIOS tell you that your current VCore is? That's always a good indicator of actual value (although in practice your VCore varies a little due to VDroop).
 
Thanks for reply.

I checked VCore in Asus AI Suite II as well as BIOS on loading. AI Suite shows exact same values as CPU-Z, it is dynamic values and depends on the load, so with Prime95 testing ON, it shows 1.200 or 1.208. Although those values can get up to ~1.250 when pc just started and still loading up (no tests are ON), I don't know what causes lower values being shown when testing, because if I understand it correctly it suppose to be a torture test. I tested with second and third options in Prime95.

This is a screenshot of my BIOS, it shows that CPU Voltage is on offset mode and is changing dynamically, values there is on idle. https://docs.google.com/file/d/0B9U4So6tJWkyc3VaemNxTWc0NUk/edit?usp=sharing

UPDATE
Actually now the max value of VCore is up to 1.240
 
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Ok, so maybe I was too ambiguous with my questions, so here is current situation. If I set windows power plan - High performance, CPU-Z starts to show voltage 1.248, and Core Speed ~ 4200 constantly, as I understand that means that CPU is running max speed all the time just it is not utilized.

Anyway, all I want to know is the voltage 1.248 is not too high for i5 3470k? I tried once to make voltage offset -0.05, but pc wont even started, crashed while loading windows. So I believe even if can to lower voltage it wouldn't be much. Maybe then I should lower the multiplier if this voltage is too high?
 
That voltage is fine. You should only get worried when the voltage gets to 1.38v, the max is 1.4v, in reality.

So you have a fair amount of voltage headroom yet.

What sort of temps are you get during prime?
 
UPDATE
Also there seem to be different number of voltage in CPU-Z and Core Temp programs, while CPU-Z shows up to 1.256, Core Temp VID field shows up to 1.31, which one I should believe?
Click to expand...

Core voltage and VID are different things. AFAIK the core voltage is what you need to be looking at. the VID is a reference table for the Auto option to follow that has been added by Intel and you dont want to be following that as you are trying to get the lowest VCore with higher clocks!
 
Ok, thanks for answers, now I feel calm about that.

My temperatures doesn't get more than 70C when prime testing on max heat although as I mention voltage goes only up to 1.200 when testing, have no idea why testing doesn't make voltage go as high as possible. Even if I have pc running on high perf and voltage is showing at 1.248, as soon as prime test starts the voltage goes down to 1.200.

As I understand going higher than 70C is not recommended, is that right?

I am just a bit frustrated that Asus FAN Xpert+ only shows CPU heat about 41C, which makes fan to run only about 900 rmp. After manual adjustment it starts run properly >1200rpm and wont allow temperatures go higher than 67-68C, but settings gets lost every time I restart PC, so that doesn't help much.

Anyway, overall I'm happy for now and probably will be for a while with current OC. Now that I know the voltage is fine, I can sleep calmly :) Thanks again.

UPDATE
Tested with Intel Burn Test on standard mode, and got max 80C temps, quite a big difference between this and prime testing.
 
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My system when using IBT my temps hover around 75-80 but in normal gaming they are averaging around 60. IBT definatly shows the highest CPU temps I've seen. It depends on who advises you but the TjMax for these chips is 105°c but i like to stick to max or around 80°c.

Your voltage drop is probably down to VDroop.
Vdroop
Vdroop is the difference between idle voltage and load voltage. The droop is actually related to the current draw of the CPU and is a peculiarity of Intel CPU design specs and as such AMD setups don't suffer from it to any great deal. Vdroop gets progressively worse as you load more cores up on multicore CPUs. Most recent Intel based boards now have the option in the BIOS to override the circuit in the motherboard power circuitry to pratically eliminate Vdroop, this is commonly called Load Line Calibration or LLC. Intel advise that enabling it may shorten the lifespan of your CPU and/or motherboard, so be aware.
Click to expand...

taken from the guide OcUK Overclocking Guide

You should have a LLC option in the BIOS somewhere which can stop/reduce the drop.
 
keep the power plan on balanced as you get to keep power saving
up to 4.2/4.3ghz the cpu will run on stock voltage,so yours is ok(about the same as mine)
also ibt stresses higher than prime and your temps wont normally get that high in gaming or normal use
 
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Now I'm using on Balanced mode constantly and its been 7 days since I restarted PC, no issues, although I haven't played any games in this period. But I did some tests and video rendering in this period and that havent interrupted pc in any way. So overall I'm quite happy.

Cooler I'm using is Thermalright HR-02 Macho.

If I will experience any problems I might try to check that LLC option, but for now things quite satisfy me.
 
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