Intel Core i7-6700: Skylake i7 at 65W

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Lawrence Lee
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Intel Core i7-6700: Skylake i7 at 65W

Post by Lawrence Lee » Sat Oct 31, 2015 4:48 pm


twig
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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by twig » Sun Nov 01, 2015 12:55 am

Thanks for the review.
While the Core i7-6700's specified TDP is 71% that of the i7-6700K, our sample failed to deliver substantial power savings. The vanilla model is undoubtedly more efficient but not by a significant margin. If you're leaning toward the non-K variant because of its seemingly lower power requirements, perhaps for a small/quiet build, the difference is too minor to weigh into the decision. The same can be said if you're considering the "K" version for its higher clock speeds; the level of performance increase is slight. The "K" model is also less formidable than in years past as Intel now allows users to overclock without adjusting the CPU multiplier. For Skylake, the base clock frequency (BCLK) can be increased independently without affecting other subsystems (PCI-E, SATA) like in the good old days of the Pentium 4 and Core 2 series.
Was this tested? It's my understanding that substantial BCLK adjustments are unavailable for Skylake non-K CPUs. I read about it second/thirdhand around or before release time (see below) but never followed up on it.
http://www.overclock.net/t/1571642/inte ... t_24357704
http://www.overclock.net/t/1570313/skyl ... t_24362348

Lawrence Lee
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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by Lawrence Lee » Tue Nov 03, 2015 12:18 am

twig wrote:Thanks for the review.
While the Core i7-6700's specified TDP is 71% that of the i7-6700K, our sample failed to deliver substantial power savings. The vanilla model is undoubtedly more efficient but not by a significant margin. If you're leaning toward the non-K variant because of its seemingly lower power requirements, perhaps for a small/quiet build, the difference is too minor to weigh into the decision. The same can be said if you're considering the "K" version for its higher clock speeds; the level of performance increase is slight. The "K" model is also less formidable than in years past as Intel now allows users to overclock without adjusting the CPU multiplier. For Skylake, the base clock frequency (BCLK) can be increased independently without affecting other subsystems (PCI-E, SATA) like in the good old days of the Pentium 4 and Core 2 series.
Was this tested? It's my understanding that substantial BCLK adjustments are unavailable for Skylake non-K CPUs. I read about it second/thirdhand around or before release time (see below) but never followed up on it.
http://www.overclock.net/t/1571642/inte ... t_24357704
http://www.overclock.net/t/1570313/skyl ... t_24362348
This was my understanding.. I couldn't find any info that contradicted it. I will test it out tomorrow.

Lawrence Lee
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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by Lawrence Lee » Tue Nov 03, 2015 11:12 am

Yup, I was mistaken. Can't get past 102 MHz. The review has been corrected.

twig
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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by twig » Wed Nov 04, 2015 3:00 pm

Cool, thanks for the update and confirmation.

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by Juventas » Thu Dec 03, 2015 10:50 am

Nice review! I'm currently running a passively-cooled i7-4770S. At a glance, it looks like the i7-6700, despite the same 65W TDP, would be generating more heat. I guess I will just have to try and see. :)

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by CA_Steve » Thu Dec 03, 2015 1:01 pm

Juventas wrote:Nice review! I'm currently running a passively-cooled i7-4770S. At a glance, it looks like the i7-6700, despite the same 65W TDP, would be generating more heat. I guess I will just have to try and see. :)
Probably not. While the i7-4770S has lower base/turbo speeds of 3.1GHz/3.9Ghz and the i7-6700 is 3.4GHz/4.0GHz, Skylake is a more efficient platform. Look at the idle power in the review: 23W for Skylake and 30W for Haswell. Light IGP loads are also less for the newer platform. Heavy IGP loads may be higher on Skylake than your Haswell CPU, but that's because there's a lot more EUs/IGP horsepower on the newer platform. I bet for heavy CPU loads, it'll be similar power use between the two SKUs.
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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by djkest » Fri Aug 26, 2016 8:39 am

With steady price decreases to CPU ($295), motherboards, and DDR4 memory, the i7-6700 is the best value in i7s now without a doubt.

The only real question is if the price premium for i7 is worth paying over say the i5-6600k which is about $75 cheaper as of right now.

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by CA_Steve » Fri Aug 26, 2016 9:09 am

djkest wrote:The only real question is if the price premium for i7 is worth paying over say the i5-6600k which is about $75 cheaper as of right now.
It really comes down to use cases. Gaming = no. HTPC = no. Lots of video editing/transcoding, 3D modeling, rendering, etc = yes.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1050 Ti Gaming, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by toptengamer » Fri Sep 30, 2016 1:09 pm

Been thinking about getting rid of my i7-3700k (OC to 4.2 GHz) in favor of something like this so I don't have to hear my CPU cooler. What kind of performance differential do you think I'd have?

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by CA_Steve » Sat Oct 01, 2016 12:34 pm

Stock i7-6700 vs 4.2GHz i7-3700k? Depends on the tasks. Your I7 will be a tad faster for items that just utilize the core functions. However, a lot of hardware accelerators (4k video, faster Quicksync, etc) have been built into the architecture over the last few years and they may blast Skylake past Ivy Bridge. Here's the stock vs stock benchmarks at Anandtech Bench.
1080p Gaming build: i5-4670K, Mugen 4, Asrock Z97 Anniversary, MSI GTX 1050 Ti Gaming, 8GB 1866 RAM, Samsung 860 Evo 500GB, Crucial MX100 256GB, WD Red 2TB, Samsung DVD burner, Fractal Define R4, Antec True Quiet 140 (2 front + rear) case fans, Seasonic SSR-550FX. 35W idle, 45-55W video streaming, 170-200W WoW, 318W stress test (Prime95 + Furmark)

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Re: Intel Core i7-6700: Skylake i7 at 65W

Post by quest_for_silence » Sat Oct 01, 2016 10:37 pm

toptengamer wrote:Been thinking about getting rid of my i7-3700k (OC to 4.2 GHz) in favor of something like this so I don't have to hear my CPU cooler. What kind of performance differential do you think I'd have?

You should not have noise issues with a 4.2GHz 3770K, if properly cooled: I'd check that, at first.

BTW, a Xeon 1230 v5 (similar but often significantly cheaper than a 6700) or a former 4790K should be other viable options for such an upgrade path.

Last but not least: out of curiosity, are you a web reviewer?
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Luca

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