Will a Z370 board alow more power to an i5-8400 compared to an H370?

[sunsanvil]

In Tom's review of the i5-8400, they say "This benchmark breaks Intel's rated TDP if the motherboard doesn't quickly rein in power consumption. Otherwise, Core i5-8400 hits values ​​well above its thermal design power, as illustrated in our chart."

I take this to mean that some mainboards will deliver more juice than others. Would we assume that a Z370 would be better than an H370, or would one H370 be better than another in this respect?

 

[feelinfroggy777]

The z370 motherboard will allow for the CPUs to run at their turbo frequency 99% of the time. The H and the B motherboards may not allow for the increased power needed to sustain the boost frequency for CPUs.

With that being said, I would worry more about paring an 8700 with a B/H board instead of the 8400 because the 8700 has a much higher TDP than the 8400.

 

[thequn]

I don't believe frog is correct in this case however toms reviews tend to push everything to to max possible throughput. That said its possible that the twinking they didn't forced the boost. But it should not really be necessary to force it and it should be fine.

 

[feelinfroggy777]

Here is a review of the new chipsets. Read the last section titled "Going Super Cheap". They review some of the power limitations. In the review they state that the 8400 could hold it's turbo and stay under the power limit of the board, but the 8700 could not hold its boost because it was requiring more watts than the board could give.

https://www.techspot.com/review/1603-intel-b360-chipset/

 

[thequn]

Oh also you may want to save some money at get the b360 is a bit cheaper to make and sale more popular for budget builds.

 

[thequn]

Frog that's. Great review thank you.

 

[sunsanvil]

Here is a review of the new chipsets.

Very good information. Thank you. I just wish they included H370 in there as well.

I'm looking at Asus' H370M-Plus and while it seems like an 8400 will be right at home, I'm wondering if an 8600 would be a limited by the board.

 

[thequn]

No processor will be limited by the MB unless your plan is not overclock in the future.or the board is defective in capacity

 

[sunsanvil]

No processor will be limited by the MB unless your plan is not overclock in the future.or the board is defective in capacity

The way I read the article feelinfroggy777 linked to, it seems that while it would be uncommon, it is possible that a board could limit a CPU's all-core turbo (as in the case of a really cheap board with a top end CPU):

"Everything looks great for the first 30 seconds, the 8700 holds 4.3 GHz on all 6-cores and we ripping through this workload. Then like that the motherboard winds the 8700 back down to 3.2 GHz for 7 seconds before cranking back up to 4.3 GHz for 8 seconds and then repeating the process. (...) The reason this is happening is because the motherboards VRM is overheating, or at least reaching the thermal limit, it then backs off the Core i7-8700’s power draw, cools a few degrees over a 7 second period and then ramps power delivery back up until the thermal limit of the VRM is once again reached, which as I just said took about 8 seconds.."

Have I misunderstood their findings?

 

[feelinfroggy777]

No processor will be limited by the MB unless your plan is not overclock in the future.or the board is defective in capacity

That used to be true but coffee lake is showing us that it is not because of the way the boost is working. The 8700 has a 65 watt TDP. But that TDP is only for the base clock of 3.2ghz. The 8700 can run 4.3ghz on all cores all day long. I know because I have one. But when the 8700 runs 4.3ghz the TDP goes a lot higher than 65 watts. So with some of the new chipsets the motherboard power delivery is not designed to sustain enough power to run at 4.3ghz. So the CPU is forced to down clock back to its base clock.

In the end, it really does not matter. It becomes an issue for the higher end CPUs like the 8700 and 8600 as these CPUs have the high boost out of the box. And if you are going to get a $250+ CPU you should at least pair it with a $100 motherboard.

 

[sunsanvil]

It becomes an issue for the higher end CPUs like the 8700 and 8600 as these CPUs have the high boost out of the box.

Personally I wouldn't have thought of the 8600 as "higher end" which is why I wanted to start this discussion.

So, if we are talking about an H370 mainboard, where is the threshold between which CPU it can satisfy and which it "hold back"? 8400 should be no problem but what about 8500? or 8600?