Intel Core i7-10700 vs Core i7-10700K Review: Is 65W Comet Lake an Option?
by Dr. Ian Cutress on January 21, 2021 10:30 AM EST- Posted in
- CPUs
- Intel
- Core i7
- Z490
- 10th Gen Core
- Comet Lake
- i7-10700K
- i7-10700
Conclusion: TDP is Not Fit For Purpose
In years gone by, processors were sold with a single frequency and power rating. It was very quickly realized that if a processor could effectively go to sleep, using either lower voltage or lower frequency (or both) then a lot of idle power could be saved. Going the other way, processor designers realized that for temporary short bursts, a core could run at a higher frequency before it reached a thermal limit. Also, using a multi-core processor meant that either the power budget could be shared across all the cores, or it could be focused in one.
Both AMD and Intel have noticed this over time, and both companies have different attitudes on how they report numbers relating to ‘base frequency’ and related power as well as the bursty ‘turbo frequency’ and related power. Out of those four metrics, the only one Intel doesn’t provide is turbo power, because from their perspective it is system dependent.
Intel lets motherboard manufacturers determine how long a system can turbo for, and what that budget is. Intel encourages motherboard manufacturers to over-engineer the motherboards, not only for overclocking, but for non-overclockable CPUs to get the best performance for longer. This really messes up what the ‘default out-of-the-box performance’ should be if different motherboards give different values. The trend lately is that enthusiast motherboards enable an unlimited turbo budget, and the user building their system just has to deal with it.
This means that users who buy the Core i7-10700 in this review, despite the 65 W rating on the box, will have to cater for a system that will not only peak around 215 W, but sustain that 215 W during any extended high-performance load, such as rendering or compute. We really wished Intel put this 215 W value on the box to help end-users determine their cooling, as without sufficient guidance, users could be hitting thermal limits without even knowing why. At this point, 'Intel Recommended Values' for turbo time and budget mean nothing outside of Intel's own OEM partners building commercial systems.
Core i7-10700 vs Core i7-10700K Performance
In the review we highlighted that these two processors have a peak turbo frequency difference of 300 MHz and an all-core turbo frequency difference of 100 MHz. The fact that one is rated at 65 W and the other is rated at 125 W is inconsequential here, given that most end-user motherboards will simply enable turbo all the time. This means the performance in most of our tests between the two is practically identical, and consummate to a 100-300 MHz frequency difference.
In practically all of our tests, the Core i7-10700K is ahead by a super slim margin. At $387 for the 10700K compared to $335 for the 10700, the performance difference is not enough to warrant the $52 price difference between the two. Performance per dollar sides mostly with the Core i7-10700, although users getting the i7-10700K will likely look towards overclocking their processor to get the most out of it – that ultimately is what to pay for.
The other comparison point is with the Ryzen 5 5600X, which has two fewer cores but costs $299. In practically every test, the increased IPC of the Ryzen over Intel means that it sits identical with the Core i7 processors, AMD is cheaper on list price, and at a much lower power (AMD will peak around 76 W, compared to 215 W). AM4 motherboards are also abundant, while corresponding Intel motherboards are still expensive. The problem here however is that AMD is having such high demand for its product lines right now that finding one in stock might be difficult, and it probably won’t be at its recommended price.
Users in this price bracket have a tough choice – the more efficient AMD processor that might be in stock, compared to the Intel processor that will be in stock but more cooling will likely be required.
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Spunjji - Wednesday, January 27, 2021 - link
The review didn't say it is a bad CPU.HarkPtooie - Tuesday, February 2, 2021 - link
Gigabyte B460M DS3HPegged at 100% CPU utilization on 8 cores (HT disabled) the wall meter says 149-163 W, CoreTemp says I use about 70 W core and 8 W uncore. CPU multiplier bounces between 43-47x, though mainly resting at 46x. Temps are 65-66°C using a humble CoolerMaster TX3 Evo.
Just upped the PL1 to 250 W in BIOS. It made no discernible difference, so I suppose it doesn't work on B460 chipsets.
Everett F Sargent - Tuesday, February 2, 2021 - link
Enable HT. If not then why not? The battery of tests conducted here and everywhere else have HT enabled. So far, you are still at the apples != oranges stage. It is now time for you to step up or ... :/Please post results with HT enabled.
Everett F Sargent - Tuesday, February 2, 2021 - link
Oh and the benchmark application that you are using (e. g. Prime95 or whatever) if you do not mind. Please. TIAHarkPtooie - Wednesday, February 3, 2021 - link
So: I set all the PL limits to max (4090 W) and reran. 173 W. Up 10-15 W from default.Then I enabled HT and reran. 213 W. +40 W compared to non-HT.
So I turned off the PL tweaking and reran, with HT on. 204 W initially, then after a while it went down to ca 140 W and the multipliers reduced to about 37x.
Kind of surprised that HT made such a difference, I was under the impression that HT "cores", being a small backpack aside the "real" core, added a tiny percent of transistors overall. I usually disable HT because the software I run don't benefit from them and actually loses performance with it.
So: mystery solved and I stand corrected.
Intel is not lying when they call this a 65 W CPU. They are however obscuring the fact that it does so with REDUCED PERFORMANCE. Its default behavior is to only run at 100% for half a minute.
When allowed by BIOS tweaks, it will double the power draw but run at 100% all the time. This is overclocking in the sense that default settings are overridden - but it is not in the sense that the peak speed is not actually driven above its intended levels. Just maintained at higher power draw.
Aight. I'm back to non-HT and free power. 173W is not that much.
Just did a compare of performance during my simulations, and they were more or less identical to the default settings.
Qasar - Thursday, February 4, 2021 - link
it is possible that the Gigabyte B460M DS3H that you are using ( as per a previous post ) could be holding the cpu back as far as overclocking, power usage and such goes. as the B460m doesnt support overclocking by intel, but asus, asrock and msi seems to have found a way to enable overclocking:https://www.techpowerup.com/266489/asrock-enables-...
https://videocardz.com/newz/asus-asrock-and-msi-br...
at the same time, though, what asus, asrock and msi have done, isnt really overclocking, but more of allowing the cpu to use its turbo states longer, then what intel allows
both of those links, could explain, at least partly, HarkPtooie, why you are getting the results you have.
Everett F Sargent - Thursday, February 4, 2021 - link
Yes, I found those links also. Conspicuously absent from all those reports was Gigabyte. But ...https://www.gigabyte.com/us/Motherboard/Intel-H470...
There you will find ...
B460M DS3H (rev. 1.0)
B460M DS3H AC (rev. 1.x)
B460M DS3H V2 (rev. 1.0)
(ranked oldest to newest afaik)
From the manual for the B460M DS3H (rev. 1.0) (page 25) ...
https://download.gigabyte.com/FileList/Manual/mb_m...
https://download.gigabyte.com/FileList/Manual/mb_m...
https://download.gigabyte.com/FileList/Manual/mb_m...
"Turbo Power Limits
Allows you to set a power limit for CPU Turbo mode. When the CPU power consumption exceeds the specified power limit, the CPU will automatically reduce the core frequency in order to reduce the power. Auto sets the power limit according to the CPU specifications. (Default: Auto)
Package Power Limit TDP (Watts) / Package Power Limit Time
Allows you to set the power limit for CPU Turbo mode and how long it takes to operate at the specified power limit. If the specified value is exceeded, the CPU will automatically reduce the core frequency in order to reduce the power. Auto sets the power limit according to the CPU specifications. This item is configurable only when Turbo Power Limits is set to Enabled. (Default: Auto)
DRAM Power Limit (Watts) / DRAM Power Limit Time
Allows you to set the power limit for memory Turbo mode and how long it takes to operate at the specified power limit. Auto lets the BIOS automatically configure this setting. This item is configurable only when Turbo Power Limits is set to Enabled. (Default: Auto)"
That same language can be found for all three MB manuals. So. it would appear that pl1, pl2 and tau are adjustable as HarkPtooie has suggested (but to be sure the latest bios version should be installed imho).
The only question I have is, why did Gigabyte apparently update the B460M DS3H (rev. 1.0) to the B460M DS3H V2 (rev. 1.0) (maybe they are different in some hardware way that I have failed to notice).
The stress test should be the one that produces the highest temperatures together with the best cooling solution possible for these non-K parts. It sounds a bit circular but then these are non-K parts where we constrain the control knobs to just pl1, pl2 and tau.
Spunjji - Monday, January 25, 2021 - link
"If you are going to make wild speculations whose veracity anyone can check, you might want to go over your material a bit better."The irony of ending your FUD with this... it's glorious!
HarkPtooie - Tuesday, January 26, 2021 - link
It would be ironic if I were wrong, but I sort of trust my eyes here. And my point was that anyone possessing an i7-10700 and a $20 wattmeter can easily check this too.Spunjji - Wednesday, January 27, 2021 - link
Good for you, but I don't trust your eyes - not when every objective review available on the internet contradicts you.