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post #11 of 22
I have a 2600k which is the same processor as yours but a different binning (ie. at the factory, the ones that clocked higher, were sold as 2700k rather than 2600k). I found that cooling wasn't a big issue, rather I seemed to hit a wall about 4.6Ghz where you'd need only a small voltage increase to go from 4.5 to 4.6, but then a massive jump to get from 4.6 to 4.7, so you might find the same. I personally drew the line at about 1.4v for voltage, as I know a lot of people run that much voltage without CPU failures (mine has been at 1.4v with no problems for about 18 months). Quite a few people do run like 1.5v (with adequate cooling) but I think you're getting to the point there where there's likely to be a noticably increased failure rate due to too much voltage.

As far as temperatures go, I'd try and keep the hottest core (measured with coretemp) under 85c, you can go hotter than that if you want, but it's good to have some margin to the maximum temperature (intel specify 97c, which is the point at which the processor would start automatically throttling down the speed to protect itself from overheating) and the generally accepted wisdom is that a cooler CPU will probably last longer.

I see by the way that you are using this for uni work, so if it's at all critical that, for example, long renders don't fail after taking up a lot of time, then I'd be really careful when you get to your final clock speed to be absolutely sure it's stable - prime95 for example takes about 16 hours to go through all the FFT sizes it can test (make sure you have the "round off checking" option selected), so to be really sure you have a stable system and won't be having BSODs etc. due to the overclock you need a really long final test, and I'd also do more than just prime95, like add in a few hours of OCCT for good measure.

Another thing that occurs to me, is that in prime95 (if that's what you're using), the "Small FFT" torture test is the best one to use to produce maximum heat (to check your cooling is adequate) and also to isolate the CPU - the "Blend" mode tests both the CPU and RAM, so is the best to use for the long final test I mentioned above.

You have 16GB of RAM, if that's as 4 x 4GB sticks, you might find (as I did) that you need some increase in vtt voltage to get stable once you get to the higher clock speeds - if I remember rightly this is the voltage to the internal memory controller on the CPU, and when the CPU is heavily overclocked, that can become unstable and need a bit more voltage. Most people don't seem to need it, but if you find you can pass prime95 small ffts, but not blend, then that points to the RAM and increasing vtt is something to consider. If I remember rightly about 1.2v is the safe limit for vtt, but don't quote me - check it elsewhere before bumping it up.
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post #12 of 22
Not entirely true about the binning.

The 2700k is basically a new revision after they got some practice in on the fabrication, Similar to the difference with the i7 920 C0 and the i7 920 D0.

Comps
post #13 of 22
Thread Starter 
Quote:
Originally Posted by BorisTheSpider View Post

I have a 2600k which is the same processor as yours but a different binning (ie. at the factory, the ones that clocked higher, were sold as 2700k rather than 2600k). I found that cooling wasn't a big issue, rather I seemed to hit a wall about 4.6Ghz where you'd need only a small voltage increase to go from 4.5 to 4.6, but then a massive jump to get from 4.6 to 4.7, so you might find the same. I personally drew the line at about 1.4v for voltage, as I know a lot of people run that much voltage without CPU failures (mine has been at 1.4v with no problems for about 18 months). Quite a few people do run like 1.5v (with adequate cooling) but I think you're getting to the point there where there's likely to be a noticably increased failure rate due to too much voltage.

As far as temperatures go, I'd try and keep the hottest core (measured with coretemp) under 85c, you can go hotter than that if you want, but it's good to have some margin to the maximum temperature (intel specify 97c, which is the point at which the processor would start automatically throttling down the speed to protect itself from overheating) and the generally accepted wisdom is that a cooler CPU will probably last longer.

I see by the way that you are using this for uni work, so if it's at all critical that, for example, long renders don't fail after taking up a lot of time, then I'd be really careful when you get to your final clock speed to be absolutely sure it's stable - prime95 for example takes about 16 hours to go through all the FFT sizes it can test (make sure you have the "round off checking" option selected), so to be really sure you have a stable system and won't be having BSODs etc. due to the overclock you need a really long final test, and I'd also do more than just prime95, like add in a few hours of OCCT for good measure.

Another thing that occurs to me, is that in prime95 (if that's what you're using), the "Small FFT" torture test is the best one to use to produce maximum heat (to check your cooling is adequate) and also to isolate the CPU - the "Blend" mode tests both the CPU and RAM, so is the best to use for the long final test I mentioned above.

You have 16GB of RAM, if that's as 4 x 4GB sticks, you might find (as I did) that you need some increase in vtt voltage to get stable once you get to the higher clock speeds - if I remember rightly this is the voltage to the internal memory controller on the CPU, and when the CPU is heavily overclocked, that can become unstable and need a bit more voltage. Most people don't seem to need it, but if you find you can pass prime95 small ffts, but not blend, then that points to the RAM and increasing vtt is something to consider. If I remember rightly about 1.2v is the safe limit for vtt, but don't quote me - check it elsewhere before bumping it up.

Hi,

Thank you very much for the response. Just to clarify, I am no longer using my computer for University work, I actually graduated in July of last year. I simply bought the system for work. As for the rest of your response, yes, I am using 4x4gb of RAM.

Ideally, like the earlier posters have said, I'd not get around to touching any voltages until, hopefully, someone could join me on a program such as Skype for text based conversation to guide me through as I really don't trust myself at all!

I have been doing some research, though, and it seems many people have managed to get results up to 4.3ghz without changing any voltages at all, which could possibly be the way I go.

As soon as I make any changes, I will run the mentioned Prim95 test and see what type of results I get.
post #14 of 22
Yes, I understand your caution, provided you do your research properly though you should be absolutely fine changing voltages a moderate amount - to see your actual CPU voltage in windows (which is different to what you set in the BIOS) you should use CPU-Z. I'd recommend keeping the power-saving features like EIST switched on in the BIOS, as these result in the CPU downclocking and lowering the voltage when it's not doing much (ie. most of the time during a normal desktop workload), which saves power and also should spare the CPU a bit since it's running at high voltage less often then.

If you just leave the voltages alone in the BIOS, you might find that doesn't achieve what you want - ie. if it's set to auto, the motherboard might give the CPU a lot of voltage to try and stabilise it at a high multiplier. You are best setting the voltage using offset mode, and using an offset that gets you the voltage you want showing in CPU-Z when loading the CPU with prime95.

I've never heard of anyone degrading a CPU with 1.4v if that helps. If you want to be really cautious, 1.35v is generally recognised as completely safe. You might have been lucky and got a 2700k that will do a high speed on very little voltage, or you might be like me and have got a fairly average CPU that needs ~1.35v for 4.5Ghz, that bit is a lottery and you won't know whether you've got a golden chip or an average one until you try.
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post #15 of 22
Thread Starter 
Quote:
Originally Posted by BorisTheSpider View Post

Yes, I understand your caution, provided you do your research properly though you should be absolutely fine changing voltages a moderate amount - to see your actual CPU voltage in windows (which is different to what you set in the BIOS) you should use CPU-Z. I'd recommend keeping the power-saving features like EIST switched on in the BIOS, as these result in the CPU downclocking and lowering the voltage when it's not doing much (ie. most of the time during a normal desktop workload), which saves power and also should spare the CPU a bit since it's running at high voltage less often then.

If you just leave the voltages alone in the BIOS, you might find that doesn't achieve what you want - ie. if it's set to auto, the motherboard might give the CPU a lot of voltage to try and stabilise it at a high multiplier. You are best setting the voltage using offset mode, and using an offset that gets you the voltage you want showing in CPU-Z when loading the CPU with prime95.

I've never heard of anyone degrading a CPU with 1.4v if that helps. If you want to be really cautious, 1.35v is generally recognised as completely safe. You might have been lucky and got a 2700k that will do a high speed on very little voltage, or you might be like me and have got a fairly average CPU that needs ~1.35v for 4.5Ghz, that bit is a lottery and you won't know whether you've got a golden chip or an average one until you try.

Well, hopefully I got one that will do more! My core volts are something like 1.008 or 0.9 at idle currently.

All I'm looking for right now really, is someone to guide me through, step by step, the process. It's a huge ask I know, but I'm happy to say that a few have come forward to help! Just unfortunately, time-zones mean arranging such is the hardest part!

I have some experience changing voltages, as I got my Q660 running at 4.0 back in the day, but that was with the help of a guy via skype who just, well, did it for me without actually touching any keys!
post #16 of 22
Oh another bit of advice, you're going to end up with a locked-up system that won't even POST and let you get to the BIOS at some point during all this (probably numerous times) - you'll have to use the "clear CMOS" switch (or jumper) to reset the board, and may even have to remove the CMOS battery while doing it, to clear everything back to defaults and get back into the BIOS. This will happen whenever you set up too high a clock speed for the voltage you have set, and the CPU is so unstable at that combination of voltage/speed, that you can't even get to the BIOS let alone get windows to boot.

Before that happens, go through your BIOS and write down your settings, so you know what to put them back to.

Also, in the same vein, write everything down as you go through the overclocking process, keeping track of what clock speeds you used and with what voltages, and at what point they threw an error in prime95. That way, you can be methodical, not waste time, and also when you get your final settings you should archive them somewhere for future, because at some point you'll likely have to reset CMOS or flash your BIOS with an update, and you don't want to have to go back and do the overclocking process again once you've found the stable settings.

I'd keep notes along these lines:

- 1.25v (-0.30 offset), 4.0Ghz, passed 1hr prime95, upping speed
- 1.25v (-0.30 offset), 4.1Ghz, passed 1hr prime95, upping speed
- 1.25v (-0.30 offset), 4.2Ghz, passed 1hr prime95, upping speed
- 1.25v (-0.30 offset), 4.3Ghz, passed 1hr prime95, upping speed
- 1.25v (-0.30 offset), 4.4Ghz, won't POST
- 1.30v (-0.25 offset), 4.4Ghz, 68c hottest core, failed prime95 after 2 hours.
- 1.35v (-0.20 offset), 4.4Ghz, 70c hottest core, passed 24 hours prime95 blend.
- 1.4v (-0.15 offset), 4.7Ghz, 80c hottest core, failed prime95 after 6 hours.
- 1.45v (-0.10 offset), 4.7Ghz, 85c hottest core, failed prime95 after 15 hours.
- 1.45v (-.0.10 offset), 4.6Ghz, 82c hottest core, passed 24 hours prime95 blend.

I don't know if that makes sense as an example, but what I mean is that you start with something you think will definitely work for at least an hour of prime. If you're not already in offset mode in the BIOS, then you're effectively at an offset voltage of zero, so you could start by putting it in offset mode, setting the offset to zero, and then set the clock speed to something that will almost certainly boot at stock voltage (like 4GHz).

You'd then boot to windows, start CPU-Z, start coretemp, start prime95 small FFTs, and check (and record) the peak voltage and temperature. Let it stress for like an hour, and if it's OK, go into the BIOS, up the clock speed a bit, and repeat until you get an error in prime, a BSOD, or it won't post.

At that point, you've got two options - drop the clockspeed back down a notch, or up the voltage. So keep choosing "up the voltage" until you reach the maximum voltage you are comfortable with (assuming temperatures are still under control) and when you reach that maximum voltage, you have only one place to go if it fails prime, BSODs or won't POST - you have to drop back down on the frequency until it's stable again.

At each intermediate point, like an hour of prime is enough to know if it's close to stable. When you get to the end stages, that's when you need to run a really long pass before calling it done and settling on the final settings.
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post #17 of 22
Quote:
Originally Posted by Oliverl1 View Post

Well, hopefully I got one that will do more! My core volts are something like 1.008 or 0.9 at idle currently.

Idle voltages don't mean much - that bit won't really change, the load voltage when running say prime95 is what matters. What do you have for that currently?
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post #18 of 22
Thread Starter 
I'm simply jealous that you guys know so much about it. I should really educate myself. I mean, I did a few years ago but never stayed up to date with it all.
I'm sure I'll get it going. I'd be happy with 4.5 for sure!
post #19 of 22
Oh, one more thing - make a restorable image backup of your machine before you even start, unless you're one of these people who doesn't mind reinstalling.

While the CPU is unstable at the intermediate points of the overclocking process, you could easily corrupt something about your windows install - you're intentionally making the machine unstable to find the limit of what speed it'll run at, so it's pretty easy to end up corrupting your OS and having to reinstall or restore from backup.
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post #20 of 22
Quote:
Originally Posted by BorisTheSpider View Post

Oh, one more thing - make a restorable image backup of your machine before you even start, unless you're one of these people who doesn't mind reinstalling.

While the CPU is unstable at the intermediate points of the overclocking process, you could easily corrupt something about your windows install - you're intentionally making the machine unstable to find the limit of what speed it'll run at, so it's pretty easy to end up corrupting your OS and having to reinstall or restore from backup.

good tip BorisTheSpider, should be in any guide about ocing ..lol
+rep wink.gif
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