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dmt_taran · ‎08-12-2018

I'll try to put it simple, just questioning what I really willing to know - but any opinion is welcome.

So, after months of experiments with my 8700k, I've chosen sweet oc spot for myself, however, that did not make me...satisfied, if I can say so.
Especially, taking into account the quality of chips that were imported to my region, I think I was lucky. No, I haven't won the golden "5.3GHz at 0.0001V®" chip, but it's capable to sustain 5GHz in AVX workload below 1.4V mark - and that is brilliant.

So, the matter why I'm consired is :
1) AVX offset doesn't have any impact on cpu stability AT ALL - despite all those reports from different users, that made CPU stable at low voltages and high clocks just implementing AVX offset.
For example, this is my CPU type of stability:
5.0 GHz, no AVX offset, 1.38V - absolutely stable.
5.1 GHz, 5.0 AVX offset, 1.38V - BSoD in 1 minute
5.0GHz, 4.5 AVX offset, 1.37V - WHEA (or BSoD if unlucky)
The same goes to any frequency I've tested.
4.8GHz, no AVX offset, 1.24V - stable 101%.
4.9GHz, 4.8 AVX offset, 1.24V - BSoD in 1 minute
4.8GHz, 4.0 AVX offset (yeah, brutal, I know), 1.23V - WHEA

2) I know, when silicon starts to hit its limits, Vcore requirements will start raise enourmosly. However, I'm not quite sure that I've reached mine's limits. Just judje for yourself - my 8700K is completely stable at 4.8GHz under 72h 100% AVX workload, within 1.24V (and that's just awesome), but can't sustain +200 MHz until voltage raised to 1.38V.
140mv for 200 mhz? - yeah, bad things happens, but I have such a feeling it isn't right. Especially considering Coffee Lake's limits about 5.2-5.3 GHz.

After all the above, I still thinking of "If I've made everything right for stable OC? Maybe I've missed something, and now pulling it in a harsh way, raising voltage above needed?"
Specs are: 8700k, maximus x her 1602, 32gb dualrank CL14 mem. The stuff is watercooled, so I don't see above 81C max under 1.38V
LLC=6, vcore is manual, SA and IO are at ~1.10V mark - thus, I have afterburned cold boot in <10sec + seems like all stuff is booted properly.

Silent_Scone · ‎08-12-2018

Not all CPU will be able to do 5.2-5.3 take a look at Siliconlottery.com findings. It is what it is, if you're needing 140mv to get stable, then the CPU simply needs the voltage.

With the AVX offset, the applied voltage is not the same for AVX and non AVX workloads due to how the VID table operates under different load conditions. You can try applying more voltage (try 1.4v for 5.1GHz with an offset of 1). The instability is likely when the load is transitioning. The truth is, you simply might just need more voltage in order to make use of the offset. I wouldn't recommend using a higher LLC than 6, either.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

dmt_taran · ‎08-13-2018

Silent Scone wrote:
Not all CPU will be able to do 5.2-5.3 take a look at Siliconlottery.com findings. It is what it is, if you're needing 140mv to get stable, then the CPU simply needs the voltage.

With the AVX offset, the applied voltage is not the same for AVX and non AVX workloads due to how the VID table operates under different load conditions. You can try applying more voltage (try 1.4v for 5.1GHz with an offset of 1). The instability is likely when the load is transitioning. The truth is, you simply might just need more voltage in order to make use of the offset. I wouldn't recommend using a higher LLC than 6, either.

VID is not applicable while manual voltage is used. It's fixed, so no voltage AAVX overshot. Simply, I'm wish to lower voltage as much as possible

Menthol wrote:
As Silent Scone said not all will do the high clocks.
Since Haswell or earlier, the best desktop CPU's will do 5.0 @ 1.3 volts vcore stable, my current 8700K is from S.L. 5.3 @ 1.423 volts tested stable, delidded on AIO.
I run it daily at 5.0, Cache 4.8 @ 1.3 volts and have benched it at 5.5 using a water chiller

Certainly the chips that require a little more volts are still good chips and any frequency above 5.0 is all gravy and only recognizable running benchmarks

Yup, the only thing I'm wish to achieve is to lower vcore requirements for 5.0 mark for everyday usage. I've used 5.1 just for example, 5GHz is more than enough for me.
I suppose, the incoming 9900K with 4.7GHz all-core stock turbo and 5GHz 2core + Intel's love to energy savings and CPUs with <1.1V, thus, I think I'll have my 5 GHz silicon soon anyway.

P.S. Actually, there IS 8700K that able to run 5GHz at lower that most cpu's stock voltages
https://www.hardwareluxx.de/community/f139/intel-coffee-lake-s-sockel-1151-oc-ergebnis-thread-kein-q...
I still doubt - however, all those results are not just bootaable clocks - it's prime stable

Silent_Scone · ‎08-13-2018

dmt.taran wrote:
VID is not applicable while manual voltage is used. It's fixed, so no voltage AAVX overshot. Simply, I'm wish to lower voltage as much as possible

Yup, the only thing I'm wish to achieve is to lower vcore requirements for 5.0 mark for everyday usage. I've used 5.1 just for example, 5GHz is more than enough for me.
I suppose, the incoming 9900K with 4.7GHz all-core stock turbo and 5GHz 2core + Intel's love to energy savings and CPUs with <1.1V, thus, I think I'll have my 5 GHz silicon soon anyway.

P.S. Actually, there IS 8700K that able to run 5GHz at lower that most cpu's stock voltages
https://www.hardwareluxx.de/community/f139/intel-coffee-lake-s-sockel-1151-oc-ergebnis-thread-kein-q...
I still doubt - however, all those results are not just bootaable clocks - it's prime stable

There is still going to be load transitioning there regardless of a fixed or adaptive voltage, though. Especially with heavy current loads. You can try changing phase control to extreme and see if this helps, however, fixed voltage or not you'll probably still need to dial it out with more vcore.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Menthol · ‎08-12-2018

As Silent Scone said not all will do the high clocks.
Since Haswell or earlier, the best desktop CPU's will do 5.0 @ 1.3 volts vcore stable, my current 8700K is from S.L. 5.3 @ 1.423 volts tested stable, delidded on AIO.
I run it daily at 5.0, Cache 4.8 @ 1.3 volts and have benched it at 5.5 using a water chiller

Certainly the chips that require a little more volts are still good chips and any frequency above 5.0 is all gravy and only recognizable running benchmarks

dmt_taran · ‎08-14-2018

So, what settings (from available in UEFI)*have a decent, noticable impact on OC stability?

Silent_Scone · ‎08-14-2018

dmt.taran wrote:
So, what settings (from available in UEFI)*have a decent, noticable impact on OC stability?

In your instance, the most likely solution whilst using the AVX offset register is increasing vcore.

13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

dmt_taran · ‎08-14-2018

Silent Scone wrote:
In your instance, the most likely solution whilst using the AVX offset register is increasing vcore.

Well, that's useless for me, cuz CPU want's the same Vcore for AVX and non AVX clock. So, no matter if I set AVX offset = 0 or -5, it is still hungry until I throw 1.38V on it.
Moreover, uncore is also negligible - cpu works flawlessly within core=uncore formula, as far as it gets it's voltage. Its hilarious that CPU requires exact the same voltage for 5GHz/4GHz AVX/4GHz uncore and 5GHz/5GHz AVX/5GHz uncore.
Right now I'm running it on 4.9/4.9/4.7 at 1.31V - smooth and easy.

I've never seen such a strange behaviour.

What has the most impact on stable OC (C/K/S Lake platform?