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I9 9900k

So I had to reinstall windows, and reseat my cooler. I also updated to the latest Asus Bios which removed the CPU Sil quality percentage for some reason.

Now I'm getting 5.1GHz @ 1.25v and I can run cinebench and Prime 95 (v29.4 build 8), I have a -1 AVX offset and I used the Torture test and small ffts since that is what others seems to be using to stress the CPU. I haven't done more than a few minutes of prime or tried any other benches so I don't know how stable it really is, but for dipping my toes in it seems decent enough to give me a starting point for the future.

I continued using cinebench and short Prime runs with the -1 AVX offset to to get some idea of where I should be voltage wise for other speeds.

Next I have 5.2GHz @ 1.3v. The AVX workload with these settings really puts the cpu on the edge of what my 40mm 360 rad can handle. I also have my GPU in the loop and the ambient temp is quite high at the mo, but even with lower ambient I think the AVX load just heats things up too much for my cooling setup right now. When not slamming the CPU with Prime everything seems fine. 33 degrees or so after a cinebench run and with a few chrome tabs and steam and battlenet open.

Going for 5.3GHz I tried all the way up to 1.4v but I couldn't get it to complete a cinebench run. This was after my previous testing so the loop was already hot and I'm still experimenting so I don't know if there are settings I can tweak to get it stable but it does boot into windows @5.3 all the way from 1.30v up. I can run HWmonitor and cpu-z etc and load cinebench but the actual run crashes.
Obviously I haven't tried Prime given the temps at 5.2 (-1) and the instability at 5.3GHz.

I could keep throwing voltage at it I guess, but I would rather take the lower number and have the CPU run cooler.

I still need to sort my loop out properly and I have a Mo-Ra 3 to add to the system so that might help with temps some, but I honestly bought it just to make the cooling as quiet as possible rather than chasing the highest overclock. Of course I will see what it is capable of, but only as a one off. :D


As for the VRMs, I don't know if there is any way of monitoring the temps but I had zero throttling and the blocks on the Formula (also in the loop) felt cool to the touch.

EDIT - it has just occurred to me (when watching the gamersnexus overclocking stream) that I have been OC with my fans on the standard profile rather than on full. I don't know if it will make a difference to the stability of the OC, but if I can handle the noise then obviously with fans on full the loop will be cooler. I'll try it another time.

Edit2 - the voltages i've listed are what i have set in the bios, not what is being reported in software.
 
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Distracted said:
With the Maximus XI motherboards, is there an option to set the CPU TDP? I have seen it mentioned with gigabyte boards I think :confused: that people were changing the TDP to 115 to allow better overclocks.
Is this something I should be doing on the Maximus Formula. Obviously I don't intend to hit that.

Edit : and what is the maximum 'safe' voltage for 24/7 use. I was looking at the sites that provide binned CPUs, including OCuk and I'm sure I read that they are using 1.35v
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Yes there is a place to set the Tjmax 115C, defaults to 100C iirc. Won't improve the clocks just the throttling point.

Maximum voltage, whatever you're comfortable within a range. The higher the voltage the more the degradation. But just core voltage isn't really the killer, it's current and heat. 1.35v - 1.4v it will degrade, but how much? Who knows, depends on the loads, but should be ok for a good while. 1.4v and up, same but sooner. The peak voltage is 1.52v, often quoted. But its not for constant use, transient spikes, overshoot LLC etc. The one to watch, which no one seems to care about is the max current Icc, now that will kill a cpu. The 9900K is 193A, say your Vc is 1.3v that's 250W. I've seen 270W with AVX on 1.3v @ 5GHz which is above spec. So 250W at the limit 193A is 1.3v, but the frequency is scaled back around 4.8 all cores.
 
fornowagain said:
Yes there is a place to set the Tjmax 115C, defaults to 100C iirc. Won't improve the clocks just the throttling point.

Maximum voltage, whatever you're comfortable within a range. The higher the voltage the more the degradation. But just core voltage isn't really the killer, it's current and heat. 1.35v - 1.4v it will degrade, but how much? Who knows, depends on the loads, but should be ok for a good while. 1.4v and up, same but sooner. The peak voltage is 1.52v, often quoted. But its not for constant use, transient spikes, overshoot LLC etc. The one to watch, which no one seems to care about is the max current Icc, now that will kill a cpu. The 9900K is 193A, say your Vc is 1.3v that's 250W. I've seen 270W with AVX on 1.3v @ 5GHz which is above spec. So 250W at the limit 193A is 1.3v, but the frequency is scaled back around 4.8 all cores.
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I've seen 1.52 as well, it seems to be from an intel document.

I assume setting the Tjmax higher than 100 in this case would only shorten the life of the cpu then, given everything else you have said.

Thank you for all the info, it's very helpful. I dont suppose you have the source for the figures so i can read some more do you?
 
Distracted said:
I've seen 1.52 as well, it seems to be from an intel document.

I assume setting the Tjmax higher than 100 in this case would only shorten the life of the cpu then, given everything else you have said.

Thank you for all the info, it's very helpful. I dont suppose you have the source for the figures so i can read some more do you?
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I heard it's been raised to 1.72v for 8 core CPU's. It's in the spec sheet for 9900k. Sounds very irresponsible though!
 
0121danwilliams84 said:
I heard it's been raised to 1.72v for 8 core CPU's. It's in the spec sheet for 9900k. Sounds very irresponsible though!
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Given the load AVX can apply I can understand why it might be increased. However, i would hope that the silicon has been tested and proven capable by intel before it was raised. Hopefully it isn't just being changed to get more out of the cpu at the expense of longevity, but i guess that is something we wont ever really know.
 
0121danwilliams84 said:
I heard it's been raised to 1.72v for 8 core CPU's. It's in the spec sheet for 9900k. Sounds very irresponsible though!
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That will be including an offset voltage. The droop on full load is pretty significant. Again, it's a range. Not the sustained, put peak voltage.

When on ln2 for instance, they pump the volts as the silicon resistance drops away. The current drops as well. Sustained high voltage will degrade, high current and temps are the killer.

0121danwilliams84 said:
seems to only be for the z390 boards. I can't find any option on my asus z370g to increase tjmax to 115.
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Quite possibly. Sorry don't have one to check.
 
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By6
Distracted said:
So, if i can find it, i could raise it to 115 and if my cpu hits 100/110 that is now considered a safe temp by intel?
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Yep that's what's it there for, it's a clever chip. It'll protect itself and throttle back when it needs to. You have an Asus? Then make use of the bios, good stuff like adaptive Vcore and the tweaker page to limit the temps and step it down on AVX loads. You never know when an app is using extended functions. Its tempting to ignore the AVX loads, don't want to limit the overclock. But that's what the throttling and bios options are there for, make use of them
 
fornowagain said:
By6

Yep that's what's it there for, it's a clever chip. It'll protect itself and throttle back when it needs to. You have an Asus? Then make use of the bios, good stuff like adaptive Vcore and the tweaker page to limit the temps and step it down on AVX loads. You never know when an app is using extended functions. Its tempting to ignore the AVX loads, don't want to limit the overclock. But that's what the throttling and bios options are there for, make use of them
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I will do. I've only done the bare minimum based on what Der8auer suggested in his OC guide, but I'll definately be going through the Bios and changing everything that needs it bit by bit.

I've set everything back to stock for now, I'll revisit the OC this weekend. I'll look at upping the cache and the ram as well as fine tuning the power delivery.

Its a lot more fun than i thought it would be.
 
Distracted said:
I will do. I've only done the bare minimum based on what Der8auer suggested in his OC guide, but I'll definately be going through the Bios and changing everything that needs it bit by bit.

I've set everything back to stock for now, I'll revisit the OC this weekend. I'll look at upping the cache and the ram as well as fine tuning the power delivery.

Its a lot more fun than i thought it would be.
Click to expand...

When I set CPU Cache to 43 it messed up my adaptive voltage. I put it back to auto and now goes to 0.700 ish idle where it was only going to 1.152v just for anyone who tries messing with cache.
 
Distracted said:
Thank you.

If i set 1.33 in bios and then hwinfo reports 1.27 - 1.323 vcore should i still be going by the setting in bios?

I saw that elmor said the boards were more accurate with the XI series but I don't know how that translates to bios settings vs hwinfo sensor readings.
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Depends on the workload and LLC setting. If you're stable under load then I wouldn't be concerned.
 
0121danwilliams84 said:
When I set CPU Cache to 43 it messed up my adaptive voltage. I put it back to auto and now goes to 0.700 ish idle where it was only going to 1.152v just for anyone who tries messing with cache.
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Thanks for that. I set mine to 43 as suggested but its back at stock now. I'll keep any eye on the voltage when i go back to it.

I've heard that oc the cache only really benefits benchmarks, but I'm interested to see it for myself.
 
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