NH-D15S performance on an i7 8700K

[x1o8x]

Hi guys,

 

Currently I'm using an NH-D15S with 2x NF-A15 fans, and my case is a Corsair Carbide 600C, and i've set an offset value of -0.08v for my cpu core voltage, so under prime95 v29.4 load, the vcore reading is at 1.200v - 1.216v and my temps are soaring to 90c on core 3 & 4, while all cores are running @ 4.7GHz.

 

The weird thing is that I'm getting similar temp readings with just one fan in the middle of my CPU cooler when I was expecting temps to drop by around 3c or so with 2 fans.

 

Could it be that my case fans are inadequate? Also is this temp normal for an i7-8700K air cooled under the specs I mentioned above?

 

Thanks in advance guys.

[Energycore]

I don't have numbers but something tells me those high temps have to do with the Coffee Lake CPUs having less than high performance TIM between the die and the IHS; which would of course be solved by delidding and applying liquid metal in between.

 

As for same temps with 1 or 2 fans, if both show 90c that might be because the CPU is throttling to stay under 90, but it throttles more on only one fan.

[Chaos Gamer]

Wait I thought the d15 and d15s were much closer in their performance

[x1o8x]

18 minutes ago, Energycore said:

I don't have numbers but something tells me those high temps have to do with the Coffee Lake CPUs having less than high performance TIM between the die and the IHS; which would of course be solved by delidding and applying liquid metal in between.

 

As for same temps with 1 or 2 fans, if both show 90c that might be because the CPU is throttling to stay under 90, but it throttles more on only one fan.

On both tests there weren't any CPU throttling that was being captured on the monitors, on both tests I've performed they've remained @ 4.7GHz until I stopped them manually. Only thing I noticed was with 2 fans, it took slightly longer to hit 90c than with 1 fan.

 

Unfortunately delidding isn't an option for me as I'd like to keep the warranty of the processor till it expires.

[Energycore]

Just now, x1o8x said:

On both tests there weren't any CPU throttling that was being captured on the monitors, on both tests I've performed they've remained @ 4.7GHz until I stopped them manually. Only thing I noticed was with 2 fans, it took slightly longer to hit 90c than with 1 fan.

 

Unfortunately delidding isn't an option for me as I'd like to keep the warranty of the processor till it expires.

Gotcha. You might honestly have to dial back the overclock or upgrade to higher performance cooling then.

[x1o8x]

Just now, Energycore said:

Gotcha. You might honestly have to dial back the overclock or upgrade to higher performance cooling then.

I've been hearing about how the NH-D15 / D15S performs similarly to most of the top end AIO coolers in the market, though I'd like to stick with air cooling for the time being due to the fact I'm paranoid when it comes to having liquid circulating inside my PC. Do you think the inadequate airflow in my case could be the issue? I only have 2x front fans and 1x rear fan on an inverted ATX case, and I've been thinking of upgrading those fans to a Noctua iPPC fans as well as adding 2 more fans on the bottom for more exhaust if that was the cause.

[Energycore]

1 minute ago, x1o8x said:

Do you think the inadequate airflow in my case could be the issue?

You can test that yourself - what temps are you getting with the side panel off, or when outside the case?

 

If you want to upgrade your fans, do the heatsink fans first, but be weary that iPPCs are loud, at all RPMs.

[x1o8x]

15 minutes ago, Energycore said:

You can test that yourself - what temps are you getting with the side panel off, or when outside the case?

 

If you want to upgrade your fans, do the heatsink fans first, but be weary that iPPCs are loud, at all RPMs.

Thanks for the tip, can't believe I forgot about that in the first place. I've slightly opened the side panel and I kind of noticed how the temps were fluctuating a little between 89c to 90c on the 3rd core, where as if I closed the side panel it stays at 90c and sometimes fluctuates to 91c so I'm guessing if I opened the whole thing and placed the PC in an more open area I'd get better temps.

 

I usually turn on my room fan and I use headphones for audio so noise isn't an issue for me. I could also control it with PWM if I find the noise level undesirable. Thanks for the help btw, I've discovered something to my high temps at unrealistic stress test for now

[Energycore]

7 minutes ago, x1o8x said:

Thanks for the tip, can't believe I forgot about that in the first place. I've slightly opened the side panel and I kind of noticed how the temps were fluctuating a little between 89c to 90c on the 3rd core, where as if I closed the side panel it stays at 90c and sometimes fluctuates to 91c so I'm guessing if I opened the whole thing and placed the PC in an more open area I'd get better temps.

 

I usually turn on my room fan and I use headphones for audio so noise isn't an issue for me. I could also control it with PWM if I find the noise level undesirable. Thanks for the help btw, I've discovered something to my high temps at unrealistic stress test for now

If you're just gaming, you need not worry about those temps as you stress your CPU. Only a couple games really stress it hard, most don't.

 

And yeah, you should see an improvement in temps by running 2000RPM NF-A14s, try setting up a fan curve with Speedfan or with your BIOS so that they're max RPM at 90c, but lower their temps to 0 as they approach 60. This way you can actually have your fans off when idling which saves a bit on their lifetime (not that you'll need that on iPPCs, those things last foreeeeeeever)

 

Edit: Looks like there are actually 3000RPM NF-A14s, though I bet those are demonically loud.

[x1o8x]

6 minutes ago, Energycore said:

If you're just gaming, you need not worry about those temps as you stress your CPU. Only a couple games really stress it hard, most don't.

 

And yeah, you should see an improvement in temps by running 2000RPM NF-A14s, try setting up a fan curve with Speedfan or with your BIOS so that they're max RPM at 90c, but lower their temps to 0 as they approach 60. This way you can actually have your fans off when idling which saves a bit on their lifetime (not that you'll need that on iPPCs, those things last foreeeeeeever)

 

Edit: Looks like there are actually 3000RPM NF-A14s, though I bet those are demonically loud.

Yea none of the games I've played have ever stressed my CPU as much as prime95 so far. I'm planning to get the 3000RPM ones as they cost the same as the 2000RPMs and they're $31 at where I live vs the regular A14 which costs $25. I'll definitely have those fans running on some profile rather than full blast all the time as the 3k RPM ones are kinda loud

 

 

[WoodenMarker]

Have you tried reseating the cooler?

[x1o8x]

3 hours ago, WoodenMarker said:

Have you tried reseating the cooler?

Yup I did that + reapplied the thermal paste, same results.

[WoodenMarker]

57 minutes ago, x1o8x said:

Yup I did that + reapplied the thermal paste, same results.

What motherboard are you using? Have you changed any other settings besides the offset voltage? Does reverting back to default help?

[LogicalDrm]

Have you tried with any other stress tests? Prime95 isn't recommended to be used with newer (after Haswell) Intel CPUs. Temps you are seeing are far from what normal use would be and higher than other reliable stress tests like Aida64, Asus RealBench and OCCT.

[x1o8x]

On 12/25/2017 at 11:42 AM, WoodenMarker said:

What motherboard are you using? Have you changed any other settings besides the offset voltage? Does reverting back to default help?

I'm using Asus Z370-F. Reverting to default makes it worse, which is why i decided to undervolt it.

 

On 12/25/2017 at 6:36 PM, LoGiCalDrm said:

Have you tried with any other stress tests? Prime95 isn't recommended to be used with newer (after Haswell) Intel CPUs. Temps you are seeing are far from what normal use would be and higher than other reliable stress tests like Aida64, Asus RealBench and OCCT.

Yea for Intel XTU I get temps around 70-75c with those stress tests. I tried Aida64 as well with the FPU and cache stress testing and I get similar temps to the prime95. I know it's unrealistic though I was hoping to gain some degrees lower with a dual fan setup only to get disappointed that I didn't.

[WoodenMarker]

16 hours ago, x1o8x said:

I'm using Asus Z370-F. Reverting to default makes it worse, which is why i decided to undervolt it.

Make sure Multicore Enhancement is turned off in the motherboard settings. It's an auto oc feature from Asus that's often turned on by default.