If I let my CPU get into the mid 60s I lose my best overclock...it runs stable without issues in the 40s though, so I don't think of it as overkill.  

 

 

 

 

TJ Max, dependent on the CPU architecture, is around 100 degrees.  40 is closer to idle than a load temp. 

 

Resistance drops with lower temps of course, decreasing the time it takes to switch states and increasing stability. But even so, mid 60's is still a low temp under load, so if not stable, increased voltage should make it so, and it would still be well under a temp that would be deemed too high. Degradation isn't really a concern until we start getting into the 80's. 

 

Regarding best overclock's... worth remembering that overclocking is linear in a well balanced system. Thus, at 30 frames per second, 100 MHz equates to less than one frame per second, and 200 MHz less than two frames per second. 

 

 

At any rate, no discussion of water should end with just AIO options, as they don't generally outperform the better air coolers like the Noctuas by much, if at all.  

 

 

 

 

It should if the OP's question was if he should opt for the Noctua or an AIO cooler. He isn't in the market for a custom loop. It's till very interesting to hear of your experiences though. Cooling is an interesting topic, regardless of cooling method.

Done some small tests

https://www.dropbox.com/s/x9qqb4pzy8vm5m1/4770k-test3-1280.png?dl=0

 

https://www.dropbox.com/s/m0ksmoo9ypse7my/Power-6700k-4770k.png?dl=0

 

Kraken X61 with noctua fans , made a bracket for the noctua fans.

https://www.dropbox.com/s/t7o5q5w3d1u7jaf/kraken-X61-noctua-fans.png?dl=0

TJ Max, dependent on the CPU architecture, is around 100 degrees.  40 is closer to idle than a load temp. 

 

Resistance drops with lower temps of course, decreasing the time it takes to switch states and increasing stability. But even so, mid 60's is still a low temp under load, so if not stable, increased voltage should make it so, and it would still be well under a temp that would be deemed too high. Degradation isn't really a concern until we start getting into the 80's. 

 

Regarding best overclock's... worth remembering that overclocking is linear in a well balanced system. Thus, at 30 frames per second, 100 MHz equates to less than one frame per second, and 200 MHz less than two frames per second.

 

Martin, I've been overclocking a long time here.  Several CPUs across several generations along the way have been able to overclock a notch higher when temps are kept well below max.  In the case of my 4790K, temps in the mid 60s start to produce blue screen crashes at my highest overclock and the highest voltage I will accept for 24/7 use.  With temps kept in the 40s, it's stable...not one blue screen in ~18 months.  If I back off the OC by 100MHz, it'll run stable in the 60s.  That effect was reproducible during my overclocking trials.  Remember also that the core temp sensors do not accurately measure other important parts of the chip die, including the IMC, and in the Devils Canyon CPUs also the on-chip regulators, so those parts of the chip might be running at temps much closer to their maximums than the cores.

 

With regards to linear performance increases, no I disagree.  Many parts of any PC run at speeds that are independent of the CPU core clocks...examples include RAM, PCIe bus, etc.  In my system, increased CPU speed does not result in higher frame rates at all, because I am synced to my 4K screen's 30Hz hardware refresh rate...increased CPU throughput does, OTOH, result in fewer and less prominent long frames (stutters) due to having an increased amount of headroom between core utilization and max core load, which enables the system to deal with occasional spikes in workload without slowing things down below a 30Hz frame rate.

 

I did not read the OP's post to indicate he was ONLY considering AIO options...he listed one as an example of what he was considering...

 

Regards

Martin, I've been overclocking a long time here.

 

 

 

No offence meant Bob. :smile:  I'm sure you have. I'm not disputing what you say, just find it unusual and something I've not come across in many years of overclocking, hence my interest.

 

 

 

In the case of my 4790K, temps in the mid 60s start to produce blue screen crashes at my highest overclock and the highest voltage I will accept for 24/7 use.  With temps kept in the 40s, it's stable...not one blue screen in ~18 months.  If I back off the OC by 100MHz, it'll run stable in the 60s.  That effect was reproducible during my overclocking trials.  Remember also that the core temp sensors do not accurately measure other important parts of the chip die, including the IMC, and in the Devils Canyon CPUs also the on-chip regulators, so those parts of the chip might be running at temps much closer to their maximums than the cores.

 

 

Well, as I say, a bit weird I feel. At 58, I've been overclocking a long time too. And this is the first time I've come across a CPU that can't handle a temp as low as 60 degrees. Regardless of the CPU architecture variables you mention. Westman is the expert in this thread, given his vast experience of so many CPU architectures and overclocking. His opinion would be interesting. But anyway, as long as you are happy it's all good. 

 

 

With regards to linear performance increases, no I disagree.  Many parts of any PC run at speeds that are independent of the CPU core clocks...examples include RAM, PCIe bus, etc.  In my system, increased CPU speed does not result in higher frame rates at all, because I am synced to my 4K screen's 30Hz hardware refresh rate...increased CPU throughput does, OTOH, result in fewer and less prominent long frames (stutters) due to having an increased amount of headroom between core utilization and max core load, which enables the system to deal with occasional spikes in workload without slowing things down below a 30Hz frame rate.

 

 

No problem, you are entitled to your opinion. However, I tested this extensively a few years ago, along with a friend. Our results were pretty conclusive. I believe Westman will also confirm that overclocking in a well balanced system is linear, according to his findings. We will have to agree to disagree then.

 

 

have been able to overclock a notch higher when temps are kept well below max

 

 

If I back off the OC by 100MHz, it'll run stable in the 60s.

 

 

 

 

And does a "notch higher" or 100 MHz offer a significant enough advantage to warrant extreme expenditure on an expensive custom loop, linear or not linear? I mean we are talking about the difference between a £60 Noctua and a custom loop costing £200, £300 maybe more.. But fair enough, as I say, the important point is that you are happy with your setup.

 

 

I did not read the OP's post to indicate he was ONLY considering AIO options...he listed one as an example of what he was considering...

 

 

 

 

The OP was deciding between the choices below, he doesn't have the budget for a custom loop. Not that it matters, It's still very interesting to discuss custom loops.

 

 

1) Keep the Hyper 212 EVO - is it really necessary to upgrade?

2) Go with the Noctua NH-D15S

3) Consider the Lepa Aquachanger 120. A budget AIO cooler that is getting great reviews. 

No worries, guys. I'm enjoying the discussion. I'm open to ideas I haven't considered since I am no expert on the matter. Plus, I hope this thread helps others.

 

Yes, I am definitely on a budget so custom water cooling is probably not an option - AIO cooling would be my best liquid option. But, honestly, if the Noctua air cooler would give me results that are just as good as a solid AIO cooler, then that's the direction I will likely go. I'm running an i7 3770k OC to 4.5 GHz using a Hyper 212 EVO. So far, it's been going well but lately I have been thinking it's time to go with something more robust, hence this thread.

NH-D15S would be much better than your Evo Todd. As long as it fits in your case. It's a big boy. you would need to make sure your RAM fits too. Shouldn't be an issue as long as it's not super tall.

 

The Lepa Aquachanger 120 you mentioned in your first post... I can't find any reviews for it, but considering it's a small 120 rad, it's not going to be anywhere near as efficient as the Noctua.

 

For an AIO to beat the Noctua, it would need to be a 280 radiator design. Thus you would need the space  in your case for such a big rad.  The mounting would also need to be compatible unless you were handy at modding.

 

Re AIO coolers, or indeed full blown custom loops... a decision that would need to be made would be orientation.

 

1. Warmer enclosure air exhausting through the rad. Thus lower enclosure temps but somewhat warmer CPU.

 

2. Cool outside air ingested through the rad. Thus cooler CPU but all that heat from the rad ingested into the case. Thus higher case temps.

 

Noctua dimensions here...

 

http://noctua.at/en/products/cpu-cooler-retail/nh-d15s/specification

Done some small testshttps://www.dropbox.com/s/x9qqb4pzy8vm5m1/4770k-test3-1280.png?dl=0https://www.dropbox.com/s/m0ksmoo9ypse7my/Power-6700k-4770k.png?dl=0

Kraken X61 with noctua fans , made a bracket for the noctua fans.https://www.dropbox.com/s/t7o5q5w3d1u7jaf/kraken-X61-noctua-fans.png?dl=0

Hasse... thats pretty much what Iv'e seen in reviews. D15 only about 5 degrees warmer than X61.

 

Did you try the X61 with Noctua fans, compared to D15 with same fans? I'd be interested in how close the D15 is to X61 both with the same fans. I wouldn't be suprised if the D15 matched it or even beat it.

Hasse... thats pretty much what Iv'e seen in reviews. D15 only about 5 degrees warmer than X61.

Did you try the X61 with Noctua fans, compared to D15 with same fans? I'd be interested in how close the D15 is to X61 both with the same fans. I wouldn't be suprised if the D15 matched it or even beat it.

Yes, fans on full speed and pwm profile, CPUs 4770k and 6700k

Have not put all together yet, "hint" the noctua fans is really good

 

Did a test with my Chiller watertemp set at 10c only to show wy a good AIO (280rad) is as close to a good customloop.

The Chiller : CPU block EK-Supermacy pumps 2xD5 in series at full speed. (adjustable from +20c down to -15c , Max load 2500w )

Customloop: 420 Monsta Rad , fans 3xNoctua Industrial 140 3000rpm, Pump Single D5 full speed, CPU block EK-Supermacy.

 

 

No problem, you are entitled to your opinion. However, I tested this extensively a few years ago, along with a friend. Our results were pretty conclusive. I believe Westman will also confirm that overclocking in a well balanced system is linear, according to his findings. We will have to agree to disagree then.

 

I also agree with this. The other parts of the system have such a trivial impact on performance when compared to the CPU, that the increase  in performance versus CPU clock speed is virtually linear.

I also agree with this. The other parts of the system have such a trivial impact on performance when compared to the CPU, that the increase  in performance versus CPU clock speed is virtually linear.

Agree

If you plan to use one of the giant sized and heavy air cooled fans/heat sink, make sure you keep your motherboard horizontal with the ground ... over time the heavy air coolers combined with the heat will flex the motherboard which could trigger a failure.

 

I prefer single water blocks that cover both CPU and chipset and VRM as they distribute mounting load across a greater surface area.

 

A chiller will bring temps lower but there is a point of diminishing returns ... chillers can be fairly noisy and require draining if you set them to be very cold ... you wouldn't want the chiller in the same room as your PC if you care about noise ... but it does sorta sound a little like an Airport external power unit

 

I use two EK XE-240 and one EK XE-120 for single CPU, Chipset, VRM water block (EK) - static pressure fans.  EK do provide a host of packaged solutions also ... not suggesting EK is the best option, but they have worked well for me in the past.

 

For flight sims, getting the most out of your CPU is important, so overclocking does help but don't expect miracles from OCs.

 

Cheers, Rob.

Rob, I believe the Noctua has a robust backplate that is mounted on the opposite side of the mobo mount. That should prevent strain on the mobo, no?

Rob, chillers ar superior to a customloop if welldisigned , compressor, condenser fans etc, not louder then air or customloop.

The only drawback you cant buy a good one at any store, most be custom made.

 

The Chiller is no option in this tread , the costs ar huge 3000-4000usd for a good one.

No reason to discuss Chillers in this tread.

I also agree with this. The other parts of the system have such a trivial impact on performance when compared to the CPU, that the increase  in performance versus CPU clock speed is virtually linear.

 

If other parts of the system are trivial, why would anyone pay big $$ for highly overclocked low-latency DDR4 RAM modules, or for overclocked Pascal GPUs?  If that's true, we shouldn't we be able to focus entirely on the CPU overclock and forget about wasting money on the rest?

 

 

@Todd--the beefier backplates prevent issues right at the CPU socket a bit better, but Rob is correct that the weight of some of the very large air coolers can torque the entire board, even well away from the socket, and eventually cause issues.  Some of those air coolers weigh 3-4 lbs, and they are tall enough to have a significant moment arm as well.  On one build I actually put a hanger with a small turnbuckle from the top frame of the case to the cooling fin assembly to provide countertorque tension, as I could see the board bending under the weight.

 

Regards

 

 

Rob, chillers ar superior to a customloop if welldisigned

 

In terms of heat extraction, agree, but you can't freeze the water so the lowest you can go is 32F ... from my experience, running a CPU at just over 32F doesn't really gain much OC potential over running at 60-70F.  So it's considerable expense for not a lot of OC return, if any.  Operating below 32F requires TEC/peltier unless you go LN route.  But operating below 0 requires more than just connect the peltier block and go ... motherboard prep, dealing with condensation, ramp time, etc. etc.  A good quality peltier requires considerable power and should not be run from the main PSU, a 2nd very high capacity PSU is the best option ... now you're at the point of exceed most homes rated Wattage output so you'll need to route a separate power circuit.  I've been down this road a couple of times and it simply was just too much work and expense for too little gain.

 

 

 

Rob, I believe the Noctua has a robust backplate that is mounted on the opposite side of the mobo mount.

 

Yes they do, as do most water blocks, but like Bob said these big air coolers extend several inches high and that increases torque (moment of force) -- dig up some old physics here ... T (torque) = r (position vector - distance from fulcrum - base of heat sink) X F (force - gravity) sin 0 (angle - vertical case so 90 degrees).

 

If you are running one of these huge heat sinks in a vertical mounted motherboard, I'd highly recommend you find a way to support the end structure of the heat sink so as to reduce the Torque being at the fulcrum.

 

I have nothing against huge air only heat sinks ... they can work well, just take into consideration their mounting and torque.  Keep in mind repeated heating On/Off in combination with torque can shorten the life of electrical components.

 

Cheers, Rob.