We begin thermals first with a truncated version of our temperature benchmarks for the i7-7700K, providing a look more exclusively at the new CPU as it differs between motherboards. We tested using both the MSI Z270 Gaming Pro Carbon ($165) and Gigabyte Aorus Gaming 7 ($240), each of which has a different auto configuration for the voltage. We also threw in manual voltage tuning for a better understanding of the 7700K’s temperatures compared to a manually tuned 6700K. These tests use the Kraken X62 cooler ($160), which was chosen so that we could look at the temperature delta between the liquid and the CPU package. As shown in our Kraken X2 series tear-down, an embedded thermocouple probe is capable of reading liquid temperatures for a better understanding of the cooler’s efficacy. This information can be used to further an understanding of the thermal transfer efficiency between the die and IHS, when studying package temperatures and coolant temperatures.
Note that all these first tests use the same settings: EIST off, Turbo off, frequency fixed to 4.5GHz on all CPUs, and CStates off. This helps control results by eliminating unpredictable fluctuations in frequency through Turbo functions. Fan and pump speeds are at maxed settings, so ~1800RPM on 2x 140mm Aer-P fans with the Gen5 Asetek pump fully loaded.
|Intel i7-7700K @ 4.5GHz
EIST 0, Turbo 0, CStates 0
|GamersNexus.net||Gigabyte G7 Auto||MSI Pro Carbon Auto||Gigabyte G7 Manual vCore|
|vCore (v)||1.356-1.404 (auto)||1.28-1.32 (auto)||1.188-1.275 (manual)|
|CPU PKG (C)||94||82||70|
|Core 0 (C)||94||82||70|
|Core 1 (C)||91||79||69|
|Core 2 (C)||94||78||70|
|Core 3 (C)||90||76||68|
|Liquid TMP (C)||29||28||28|
|PKG PWER (W)||133-135
For the first test, we’re focusing on the Gigabyte Z270 Gaming 7 motherboard being tortured with large Fourier transforms for half an hour. The i7-7700K is constantly in the 90C range, occasionally hitting 94C. Ambient was 21-22C for all these tests, so our temperature range is roughly +/- 1C. Active logging was performed with logging thermometers and thermocouples to ensure accuracy of ambient.
This was the first board we tested, so the immediate concern was that Kaby Lake would run way too hot. With the same stock configuration on the Gigabyte Gaming 7 board, a $50 Be Quiet! Dark Rock 3 air cooler was hitting 100C routinely, resulting in throttles upwards of 200MHz. Our Asetek 570LC fat 120mm cooler with Gentle Typhoon fan also was approaching 100C.
Clearly, something seemed wrong. Further investigation revealed that the motherboard was pushing voltages as high as 1.404v at times, which is wholly unnecessary. The MSI Z270 Gaming Pro Carbon motherboard, meanwhile, produced an auto-configured voltage of about 1.28v to 1.32v, with a corresponding temperature range of 80-82C max. This is with a package power that’s reduced around 27W from Gigabyte’s, but with exactly the same frequency performance.
We then dropped the Gigabyte board down to 1.275v manually, giving it a range of 1.188 to 1.275v. This brought temperature down from 94C max to about 70C max, or a 24C difference (same configuration, test platform, and ambient) as a result of better, manual vCore control. This is less an Intel problem and more of a Gigabyte problem. We have been in communication with all three motherboard vendors since our temperature testing began (about 1-2 weeks ago), and have made Gigabyte aware of the issue. Fortunately, the unnecessarily high auto voltage is something that is resolvable through firmware updates. If Gigabyte got ahead of the game, they may be able to roll-out BIOS patches prior to board shipment – but we’re not sure right now, and certainly can’t rely on that.
This mystery solved, the next question pertained to Skylake. We wanted to know whether Kaby Lake has any meaningful temperature change versus Skylake, particularly the i7-6700K.
|Intel i7-7700K & i7-6700K @ 4.5GHz
EIST 0, Turbo 0, CStates 0
|GamersNexus.net||Intel i7-7700K||Intel i7-6700K||Intel i7-6700K||Intel i7-7700K|
|MSI Pro Carbon Auto||MSI M7 Auto||MSI M7 Manual vCore||Gigabyte G7 Manual vCore|
|vCore (v)||1.28-1.32 (auto)||1.32 (auto)||1.188-1.275 (manual)||1.188-1.275 (manual)|
|CPU PKG (C)||82||72||64||70|
|Core 0 (C)||82||70||63||70|
|Core 1 (C)||79||72||64||69|
|Core 2 (C)||78||68||61||70|
|Core 3 (C)||76||68||61||68|
|Liquid TMP (C)||28||29||29||28|
|PKG PWER (W)||101-104
Using the MSI Gaming M7 Z170 and i7-6700K with all auto settings, we’re producing a temperature of about 72C on the package. The vCore was 1.32v. This is already cooler than the comparable MSI Z270 Gaming Pro Carbon benchmarks, despite running a higher reported wattage. Looking at the 1.88-1.275v tuned tests shows a delta of about 6-7C between Kaby Lake and Skylake. We do not have definitive enough data to declare that Kaby Lake is hotter – we’d have to do further testing with more motherboards between each CPU – but this certainly shows the 7700K warmer in our tests.
This is potentially because the i7-7700K is having more trouble transferring its heat to the IHS. That could be more of a per-chip lottery, though we’ve validated on two samples and see similar results on each. A lot of this is also on Gigabyte, keep in mind.