[News] Leaked Intel Core i7-7700K Sample Tested [Update: Retested]

[StyM]

https://www.techpowerup.com/228282/l...-sample-tested

The team over at Tom's Hardware have gotten their hands on Intel's new 'Kaby Lake' CPU - The Core i7-7700K. While the chip is not marked as an engineering sample, they cannot confirm with confidence that it is a retail part. They then did what we all hoped and expected, they put the new i7 through a series of benchmarks both at its stock speeds and overclocked. Without a retail Z270 series motherboard to test with, Kaby Lake compatible firmware was loaded onto their Gigabyte GA-Z170X-Ultra Gaming board.

In line with what has been reported so far, the stock clock speeds of their sample was 4.20GHz base and 4.50GHz max turbo boost with a TDP of 95W, up marginally from the i7-6700K's 91W. As tested the 7700K drew slightly more power under load than the 6700K whilst achieving benchmark results that are more-or-less in line with the percentage clock speed increase. Using the same core voltage for overclocking, the 7700K was able to manage a 4.8GHz overclock at 1.3v where the 6700K achieved 4.6GHz. As Intel did not change the core micro architecture between Skylake and Kaby Lake, it appears that save for HEVC and VP9 8/10-bit encode/decode and other possible features we may not yet know of, slightly faster clock speeds is the principal improvement. Given this is a pre-release test conducted on a motherboard that may not be able to unleash the full potential of the i7-7700K, the results should be taken with their appropriate pinch of salt. For the article and detailed findings, please follow the source link.

[AliG]

Wait that doesn't make sense. I thought Kaby Lake was supposed to be very slightly more power efficient - but the first graph clearly shows it consuming much more at stock speeds?

[StAndrew]

Higher stock speeds than the 6700?

[AliG]

Higher stock speeds than the 6700?

My understanding was the higher speeds were a result of fitting in the same power envelope due to increased efficiency. I'll buy a slight increase in wattage, but 133 vs 183 is huge.

[StAndrew]

I'm not sure why there are two graphs but the second one looks more accurate

[StAndrew]

First chart:

We’re also told that process improvements will enhance efficiency, but there is no free lunch. Intel didn’t change the core micro architecture between Skylake and Kaby Lake, and our motherboard didn’t even read a voltage reduction for the Core i7-7700K, compared to the Core i7-6700K. Our motherboard set the Core i7-7700K to 1.30V at its 4.50 GHz max turbo, whereupon it behaved exactly the way we’d expect our Core i7-6700K to act when overclocked to 4.50 GHz at 1.30V

Second chart:

This particular motherboard dropped the full-load CPU voltage by around 20mV and the maximum full-load multiplier to 42x after I changed from firmware defaults to manual configuration and then back to automatic settings. It did this twice, both times after I initially used the CLR_CMOS jumper. Maximum power draw then dropped to 141W when turbo boost was disabled (bringing us down to the default 4.20 GHz; see chart below). Idle energy also dropped to 24W after several hours, but an idle period of that length exceeds normal test procedure.

The “no free lunch” statement still applies since 141W is more than 133W, but the only way I’ll reach an accurate conclusion about how much more power the higher 4.50 GHz frequency requires is to compare more boards. The new generation of motherboards that launch with this CPU will be the best boards to use for those tests, and we’ll have a batch of them ready when the NDAs of those manufacturers expire.

[AliG]

Ohhhhhh.

That makes so much more sense (though is not at all obvious from the graph).

[StAndrew]

Updated:

http://www.tomshardware.com/news/int...ate,33119.html

I think results will be a little better when proper firmware is released but I wouldn't expect anything ground breaking here. Maybe for guys like me running dinosaur era i7's...

[StyM]

http://www.tomshardware.com/news/int...ate,33119.html