The Intel i7-6700K Review; Skylake Arrives
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System Power Consumption
Our power consumption numbers are broken down into two categories: one which simply stresses all of the CPU cores with WPrime and another which puts a high amount of load on both the CPU cores and the IGP. The latter will only be included if a given processor includes a dedicated internal graphics sub-processor.
For the CPU power consumption test, we use the standard testing system (with an NVIDIA GTX 980 installed) and wait until the system and discrete GPU are at idle speeds in order to log the idle power consumption. After this, WPrime 1024M is looped for 15 minutes while the power consumption is logged with a calibrated power meter to determine the average watts.
The first set of power consumption tests show the i7-6700K is relatively power efficient given its overall performance but we can’t forget this is a 91W processor going up against predecessors that have lower TDPs. The reason for this is simple: Skylake K-series chips have more Smart Cache than Broadwell processors and an expanded design in comparison to Haswell.
With that being said, the idle results were quite surprising but that may be due to immature firmware rather than anything else.
Without the discrete graphics card plugged in, the result are basically the same though we can see the i7-6700K gets quite a bit more competitive. This leads us to believe there may be a PCI-E power bug but again, that’s only a theory.
The i7-6700K’s graphics performance strides within the massive gap between Intel’s Devil’s Canyon and Broadwell 5775C and that’s exactly where the power consumption ends up as well.
System Power Consumption
Our power consumption numbers are broken down into two categories: one which simply stresses all of the CPU cores with WPrime and another which puts a high amount of load on both the CPU cores and the IGP. The latter will only be included if a given processor includes a dedicated internal graphics sub-processor.
For the CPU power consumption test, we use the standard testing system (with an NVIDIA GTX 980 installed) and wait until the system and discrete GPU are at idle speeds in order to log the idle power consumption. After this, WPrime 1024M is looped for 15 minutes while the power consumption is logged with a calibrated power meter to determine the average watts.
The first set of power consumption tests show the i7-6700K is relatively power efficient given its overall performance but we can’t forget this is a 91W processor going up against predecessors that have lower TDPs. The reason for this is simple: Skylake K-series chips have more Smart Cache than Broadwell processors and an expanded design in comparison to Haswell.
With that being said, the idle results were quite surprising but that may be due to immature firmware rather than anything else.
Without the discrete graphics card plugged in, the result are basically the same though we can see the i7-6700K gets quite a bit more competitive. This leads us to believe there may be a PCI-E power bug but again, that’s only a theory.
The i7-6700K’s graphics performance strides within the massive gap between Intel’s Devil’s Canyon and Broadwell 5775C and that’s exactly where the power consumption ends up as well.
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Overclocking Results
There are some serious expectations attached to Intel’s K-series chips and they’ve delivered in most situations. During my short time with the i7-6700K I can say that it didn’t stand out as being exceptional but that’s not to say this architecture isn’t capable of accomplishing some incredible things. With the additional BCLK granularities Intel has given you, there should be some finer grain adjustments for dialing in overclocks but unfortunately I haven’t had the sample in hand long enough to explore its limits.
With that being said, the ASUS Deluxe has an automatic setting that automatically overclocked our CPU to 4.6GHz. That would have been the easy way out and it does provide quick way to achieve a stable overclock with a minimum of effort.
After a few hours of tuning the CPU (memory wasn’t touched in this instance) a perfectly 3D stable frequency of 4.823GHz was achieved on all four cores. The system did tend to lock up when going north of 4.85GHz and completely refused to POST at 4.9GHz but nonetheless I’m quite happy with the end result.
Overclocking Results
There are some serious expectations attached to Intel’s K-series chips and they’ve delivered in most situations. During my short time with the i7-6700K I can say that it didn’t stand out as being exceptional but that’s not to say this architecture isn’t capable of accomplishing some incredible things. With the additional BCLK granularities Intel has given you, there should be some finer grain adjustments for dialing in overclocks but unfortunately I haven’t had the sample in hand long enough to explore its limits.
With that being said, the ASUS Deluxe has an automatic setting that automatically overclocked our CPU to 4.6GHz. That would have been the easy way out and it does provide quick way to achieve a stable overclock with a minimum of effort.
After a few hours of tuning the CPU (memory wasn’t touched in this instance) a perfectly 3D stable frequency of 4.823GHz was achieved on all four cores. The system did tend to lock up when going north of 4.85GHz and completely refused to POST at 4.9GHz but nonetheless I’m quite happy with the end result.
Conclusion; A Good CPU, An Awesome Platform
In what has been a challenging year for Intel their Skylake architecture stands out as a shining example of what can be achieved in the face of adversity. Indeed, Intel’s ode to overclockers and gamers with an early launch of some key processors like the i7-6700K will likely stoke the fires of excitement and quicken adoption rates. And there’s a lot to be excited about here.
As someone who currently games and works on an i7-4790K based system I’ll be the first to say that Haswell and especially Devil’s Canyon users won’t see any tangible performance benefits in most applications. Intel’s lock-step intergenerational improvements of about 10% continue here just like they did with Ivy Bridge, Haswell and Broadwell so some enthusiasts will likely want to roll their eyes and say “I’ll wait for whatever comes next”. However anyone still on the Sandy Bridge or Ivy Bridge platform will likely see a noticeable speedup in everything from gaming to video conversion to photo processing.
The 20% improvement over a comparable i7-4770K may be a minimal number for many of you reading this but we can see where Intel focused their microarchitecture update efforts in the move from the Haswell to Broadwell to Skylake. In tests that use x86 instruction sets, engage a single processing thread or cause another component to bottleneck things, gains over Haswell-generation CPUs will be minimal at best. Other applications which use newer instruction sets like AVX2 and SSE4.1 see stratospheric improvements and as additional programs roll those features, we can expect the gap between old and new to widen further. More importantly, many of these benefits have been achieved on a processor that has a 5% lower Turbo clock than an i7-4790K, proving that despite frequency stagnation IPC rates continue to rise.
Skylake’s benefits in games are a bit more nebulous since, once you get to the detail levels and resolutions most folks play at when plunking down $350 on a new processor, the GPU will become a bottleneck long before an i7-6700K starts slowing things down. DX12’s multi-threaded algorithms may change this equation but we won’t know by how much until the API rolls into new titles.
On the integrated graphics side of this equation the i7-6700K is a bit of a mixed bag. When compared against the HD 4600 found in higher end Haswell and Devil’s Canyon processors, Skylake’s HD 530 processor graphics engine is significantly better in every way imaginable. However, contrast this to the impressive numbers put forth by Broadwell processors like the i7-5775C which are equipped with the Iris 6200 and you can see that sacrifices were made to achieve a set of performance goals. Intel knows their clients will supplement these new processors with a dedicated graphics card in nearly every situation so a high output integrated graphics engine wasn’t really needed. This allowed for a greater focus on higher clock speeds and enhanced performance in key metrics where raw CPU processing still counts.
The real benefits of Skylake versus previous architectures ultimately rests on the laurels of its very capable platform. By integrating twenty PCI-E Gen3 lanes into the Z170 chipset, Intel has engineered a solution that has sufficient overhead to deal with current and upcoming high bandwidth devices while also bringing advanced storage options to a broader spectrum of users. While support for full speed NVMe, M.2 and USB 3.1 was certainly achievable on Z97 and earlier boards, the Z170 PCH insures they can all be integrated without any extreme sacrifices or expensive PCI-E switches. This future proofing was necessary as Intel expects this platform to remain around for quite a while.
While I didn’t have quite enough time with the motherboard and CPU sample to make anything but the most rudimentary comments about overclocking, the i7-6700K seemed to be a willing participant. Temperatures remained good under a simple Corsair AIO, it reacted as expected to additional voltage and relative performance increases were quite impressive. ASUS grants an almost unlimited number of options on their higher end boards like the Z170 Deluxe and I’ve only just begun to explore what may be achieved when some of the more exotic settings are used in conjunction with Skylake’s additional BCLK and memory speed granularity. There’s certainly more left in the tank but it’s impossible to know how much until more skilled overclockers get their hands on these chips.
But what about competition? Well, simply put, there is none. AMD’s current desktop architecture isn’t even in the same time zone as Intel’s higher end Haswell chips, let alone Skylake. It’s come to a point where the very best APUs AMD can produce struggle to provide barely half the performance of current generation Core-series chips. The A10-7870K was included in this review as a perfect demonstration of what happens when x86 performance is sacrificed generation after generation for better graphics throughput.
Despite being extremely happy with Skylake I do have some minor points of criticism. First and foremost is pricing. At $350 the i7-6700K isn’t cheap but it is right in line with previous generations’ cost models but the Z170 platform will likely be an expensive upgrade for many. Thus far it looks like the motherboards will initially be between $15 to $40 more expensive than their predecessors and the added cost of DDR4 memory also needs to be factored into the equation. These aspects will likely iron themselves out as DDR4 production capacities increase and Z97 motherboards begin to enter EOL status, allowing vendors to reduce or eliminate Z170’s premiums.
There were two other minor hiccups during testing, one of which was power consumption. From a performance per watt standpoint the i7-6700K aligns well with previous architectures but there’s no real improvement per se and idle consumption was a bit higher than expected. It also took a significant number of BIOS modifications and reboots to actually get Intel’s SpeedStep to work on our processor. Both of these were likely due to relatively immature firmware rather than an underlying problem with the architecture.
Intel’s official Skylake reveal with its full array of SKUs and architecture details may be a few weeks away but what we’ve seen so far is certainly impressive. The i7-6700K, i5-6600K and Z170 platform may only be tasty appetizers before the main course is served but if first impressions are anything to go by, this processor generation may be one of the most popular in recent memory. While the i7-6700K didn’t really blow my mind with its benchmark numbers, it provides more than enough performance uplift over previous generations to justify upgrading a pre-Haswell generation system. As higher bandwidth SSDs and USB 3.1 devices become increasingly widespread, even Z97 and Z87 users may start jumping ship into Z170’s waiting arms. It will certainly be interesting to see what the rest of Intel’s Skylake lineup will look like.
Conclusion; A Good CPU, An Awesome Platform
In what has been a challenging year for Intel their Skylake architecture stands out as a shining example of what can be achieved in the face of adversity. Indeed, Intel’s ode to overclockers and gamers with an early launch of some key processors like the i7-6700K will likely stoke the fires of excitement and quicken adoption rates. And there’s a lot to be excited about here.
As someone who currently games and works on an i7-4790K based system I’ll be the first to say that Haswell and especially Devil’s Canyon users won’t see any tangible performance benefits in most applications. Intel’s lock-step intergenerational improvements of about 10% continue here just like they did with Ivy Bridge, Haswell and Broadwell so some enthusiasts will likely want to roll their eyes and say “I’ll wait for whatever comes next”. However anyone still on the Sandy Bridge or Ivy Bridge platform will likely see a noticeable speedup in everything from gaming to video conversion to photo processing.
The 20% improvement over a comparable i7-4770K may be a minimal number for many of you reading this but we can see where Intel focused their microarchitecture update efforts in the move from the Haswell to Broadwell to Skylake. In tests that use x86 instruction sets, engage a single processing thread or cause another component to bottleneck things, gains over Haswell-generation CPUs will be minimal at best. Other applications which use newer instruction sets like AVX2 and SSE4.1 see stratospheric improvements and as additional programs roll those features, we can expect the gap between old and new to widen further. More importantly, many of these benefits have been achieved on a processor that has a 5% lower Turbo clock than an i7-4790K, proving that despite frequency stagnation IPC rates continue to rise.
Skylake’s benefits in games are a bit more nebulous since, once you get to the detail levels and resolutions most folks play at when plunking down $350 on a new processor, the GPU will become a bottleneck long before an i7-6700K starts slowing things down. DX12’s multi-threaded algorithms may change this equation but we won’t know by how much until the API rolls into new titles.
On the integrated graphics side of this equation the i7-6700K is a bit of a mixed bag. When compared against the HD 4600 found in higher end Haswell and Devil’s Canyon processors, Skylake’s HD 530 processor graphics engine is significantly better in every way imaginable. However, contrast this to the impressive numbers put forth by Broadwell processors like the i7-5775C which are equipped with the Iris 6200 and you can see that sacrifices were made to achieve a set of performance goals. Intel knows their clients will supplement these new processors with a dedicated graphics card in nearly every situation so a high output integrated graphics engine wasn’t really needed. This allowed for a greater focus on higher clock speeds and enhanced performance in key metrics where raw CPU processing still counts.
The real benefits of Skylake versus previous architectures ultimately rests on the laurels of its very capable platform. By integrating twenty PCI-E Gen3 lanes into the Z170 chipset, Intel has engineered a solution that has sufficient overhead to deal with current and upcoming high bandwidth devices while also bringing advanced storage options to a broader spectrum of users. While support for full speed NVMe, M.2 and USB 3.1 was certainly achievable on Z97 and earlier boards, the Z170 PCH insures they can all be integrated without any extreme sacrifices or expensive PCI-E switches. This future proofing was necessary as Intel expects this platform to remain around for quite a while.
While I didn’t have quite enough time with the motherboard and CPU sample to make anything but the most rudimentary comments about overclocking, the i7-6700K seemed to be a willing participant. Temperatures remained good under a simple Corsair AIO, it reacted as expected to additional voltage and relative performance increases were quite impressive. ASUS grants an almost unlimited number of options on their higher end boards like the Z170 Deluxe and I’ve only just begun to explore what may be achieved when some of the more exotic settings are used in conjunction with Skylake’s additional BCLK and memory speed granularity. There’s certainly more left in the tank but it’s impossible to know how much until more skilled overclockers get their hands on these chips.
But what about competition? Well, simply put, there is none. AMD’s current desktop architecture isn’t even in the same time zone as Intel’s higher end Haswell chips, let alone Skylake. It’s come to a point where the very best APUs AMD can produce struggle to provide barely half the performance of current generation Core-series chips. The A10-7870K was included in this review as a perfect demonstration of what happens when x86 performance is sacrificed generation after generation for better graphics throughput.
Despite being extremely happy with Skylake I do have some minor points of criticism. First and foremost is pricing. At $350 the i7-6700K isn’t cheap but it is right in line with previous generations’ cost models but the Z170 platform will likely be an expensive upgrade for many. Thus far it looks like the motherboards will initially be between $15 to $40 more expensive than their predecessors and the added cost of DDR4 memory also needs to be factored into the equation. These aspects will likely iron themselves out as DDR4 production capacities increase and Z97 motherboards begin to enter EOL status, allowing vendors to reduce or eliminate Z170’s premiums.
There were two other minor hiccups during testing, one of which was power consumption. From a performance per watt standpoint the i7-6700K aligns well with previous architectures but there’s no real improvement per se and idle consumption was a bit higher than expected. It also took a significant number of BIOS modifications and reboots to actually get Intel’s SpeedStep to work on our processor. Both of these were likely due to relatively immature firmware rather than an underlying problem with the architecture.
Intel’s official Skylake reveal with its full array of SKUs and architecture details may be a few weeks away but what we’ve seen so far is certainly impressive. The i7-6700K, i5-6600K and Z170 platform may only be tasty appetizers before the main course is served but if first impressions are anything to go by, this processor generation may be one of the most popular in recent memory. While the i7-6700K didn’t really blow my mind with its benchmark numbers, it provides more than enough performance uplift over previous generations to justify upgrading a pre-Haswell generation system. As higher bandwidth SSDs and USB 3.1 devices become increasingly widespread, even Z97 and Z87 users may start jumping ship into Z170’s waiting arms. It will certainly be interesting to see what the rest of Intel’s Skylake lineup will look like.
