Reported throttling on 8th gen mobile chips. | PCSPECIALIST

Reported throttling on 8th gen mobile chips.

Rob574188

PC Specialist
Hi Guys,

Recently we have had a lot of people unsure as to normal behaviour for the i7-8750H, i7-8850H and i9-8950HK. Our research manager has been working tirelessly testing several different models of laptop from different manufacturers in order to clear this up and absolutely confirm the expected behaviour of these chips.

With current laptop trends meaning chassis are getting thinner but core count and clock speed are increasing meaning it is becoming more the case of balancing power usage (and thermals) and performance. While this struggle is also present in desktop machines, the extra real estate available for cooling options here makes this much less noticeable.

For this reason, inherently, mobile chips do throttle and this is as per design and this is even more so when using battery. The “rated” turbo is for 1 core under certain criteria this then drops for 2 core load and again for 3,4,5,6 core loads.

I will include a small sample of real world game testing that our research team did with the I7-8750H in case anyone is interested.

Final Fantasy XV
3.92 CPU frequency peak
3.09 CPU frequency average
92 Peak temperature
84 Average temperature
2 Average core load
Current Limit throttling during level load but not during game play

Project Cars 2
3.97 CPU frequency peak
3.85 CPU frequency average
79 Peak temperature
73 Average temperatre
1 Average core load
Current Limit Throttling operates during gameplay intermittently, no slow down seen

FarCry5
3.85 CPU frequency peak
3.62 CPU frequency average
93 Peak temperature
85 Average temperatre
4 Average core load
Current Limit Throttling operates during gameplay intermittently, no slow down seen

RealBench – synthetic load comparison
2.6 CPU frequency peak
2.1 CPU frequency average
95 Peak temperature
84 Average temperatre
6 Average core load
Current Limit and Power Limit Throttling Active for the whole time during the stress test.

From what we have observed here we do believe that any of the excessive throttling observed seems to be linked to applications utilising AVX instructions for instance AIDA64 and the intel XTU software.

For clarification, there are 2 main types of throttling. Power limit throttling and Thermal throttling. Power limit throttling is put in place to balance power usage, generally between the GPU and CPU especially when under intensive use. This isn’t really an issue so much as a feature. Regarding thermal throttling, this does not always mean that the chip is performing outside of specification but rather that clock speeds are being limited in order to perform within the chips thermal specification. Excessive thermal throttling IS an issue but a little thermal throttling won’t generally make too much difference with regards to real world performance.

Of course if anyone does want any further clarification or if you have any questions we are happy to help.
 
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