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A Funny Thing Happened on the Way to 5 GHz

Level 11
For the past couple of weeks, I've been testing various BIOS configuration with the following intent:

  • Reducing CPU core temperatures
  • Reducing manual voltage settings or eliminating unneeded manual voltage settings
  • Determining the maximum stable DRAM settings
  • Determining the maximum stable CPU settings

I've tried more combinations than I care to admit and kept ending up with AIDA64 stability test results that crashed at different times.

And then, quite by accident, I noticed that increasing the BCLK would increment or decrement the "Target DMI/PEG Clock".

Between BCLK 125 to 126.2, the "Target DMI/PEG Clock" would return to 100 MHz.

At that point, setting the BCLK to 126.2 allowed:

  • A stable CPU core frequency of 5048 MHz on all four cores
  • A stable CPU cache frequency of 4788 MHz
  • A stable DRAM frequency of 2524 MHz
  • A maximum average CPU core temperature in the mid to low 70s
  • Many of the voltage settings were able to be set to Auto or remarkably lower than previous manual settings


Hello Denna

It looks like you got it sorted to me, that is one nice overclock with the nepton 140xl.

In fact it is outstanding nice job , is this with hyperthreading enabled?

Level 11

Hyperthreading is enabled.

I was also stability testing under the conditions the system would be used - with regular background programs running (i.e., anti-virus, firewall, mouse software, etc.).

While it's not shown in the profile, the system is configured to reduce heat containment and maximize airflow.

  • The Corsair 350d case has 6 x Akasa Apache 140mm fans, 1 x Akasa Apache 120mm fan and 1 x Titan Extreme 95mm fan in a custom blower fan I designed to sit next to the GPU VRMs for exhaust. All fans and pumps are running at 100% because they're almost inaudible.

  • All cables are routed behind the motherboard.

  • The inside of the system is packed with about 7 lbs of Acoustipack soundproofing that reduces the interior volume.

  • The front panel isn't on right now, but I'll be modding the front panel for safety and to maintain good airflow.

Due to space issues, the system only has 2 x 140mm AIO radiators. I've been thinking of a way to extract heat from the radiators without causing condensation.

If there's a way to further reduce system heat, I'd like to hear it.

II think your temps are great !

I've heard of people using water wetter to reduce temps, I've never used it so I can only go on what other people say about it. I don't know if I would use it though. What would be the best way to lower temps is lower the ambient air temp or get a water chiller.

Then of course you have phase change and liquid nitrogen.


Since these are AIO closed loop coolers, the option to modify them internally would be a messy risk.

Thanks for the water chiller suggestion. I was thinking of a solution similar to that, but without having to tap the AIO cooler.

Luckily, the room is air conditioned - which was a necessity for CPU testing, not so much for memory testing.

As for sub-zero cooling ... that's another day with another build. And not too soon I hope.

Level 40
Water wetter only helps in that it stops formation of vapour at very hot heat transfer surfaces....i.e stops bubbles forming when water is boiling...allows water to contact surface better....this, I very much hope, is not the case at the contact point with your CPU....

In fact it would worsen heat transfer in a typical PC loop......

Yeah water wetter is for cars more than pc water cooling, that's why I probably wouldn't use it but good luck to those that do.

Thanks for pointing that out Arne. 🙂

You might be better off just building a custom loop but in all honesty if you're getting the temps you are now, I don't see how a custom loop would benefit much.

There is a member here named meankeys you can do what he did and this would work just as good or better than a chiller. He just got a picnic cooler filled it with ice and water then had a spiral copper tube as part of the loop for the liquid to flow through submerged in the ice water. That would be a cheap and very effective way to do it.

I will say those all in one coolers might not have a strong enough pump to do it.

How were you thinking to do it? Give me some of your ideas.

Level 11

I haven't formalized an idea yet, but it would have to be a quiet, compact, non-invasive add-on to an AIO CLC to reduce temperatures by at least 15C.

  • It might provide a bit more overclocking headroom if the system is thermally limited.

  • It should make the system quieter if fan profiles are linked to rising temperatures.

  • It might delay component failure due to extended periods of performing at its thermal maximum.

Basically, a heat exchanger.

Hmmm it might be difficult to find something that can add to your radiator and drop temps 15c. A heat exchanger is pretty much a radiator and I don't see adding another rad dropping temps 15c.


I wasn't thinking of adding another radiator.

The wheels are just starting to turn, so a clear design has yet to materialize.