I5

Today we are dealing with one of the Intel flagship for the LGA1151 socket, it is the new Intel Skylake processor : i5-6600k with unlocked multiplier. The tick with the most tock sensation that we have been able to try during this decade.

On paper we find improvements in temperature, greater overclocking capacity, the new Z170 chipset and the incorporation of the Intel HD 530 graphics card.

Ready for our analysis ? Well here we go!

Technical characteristics i5-6600k

Processor	Core i7-5775C	Core i5-5675C	Core i7-6700K	Core i5-6600K	Core i7-4790K	Core i7-4770K
Name	Broadwell	Broadwell	Skylake	Skylake	Haswell	Haswell
Socket	LGA1150	LGA1150	LGA1151	LGA1151	LGA1150	LGA1150
Core / Thread	4/8	4/4	4/8	4/4	4/8	4/8
Frequency (GHz）	3.3-3.7	3.1-3.6	4.0-4.2	3.5-3.9	4.0-4.4	3.5-3.9
Memory	DDR3-1600	DDR3-1600	DDR4-2133	DDR4-2133	DDR3-1600	DDR3-1600
IGP	Iris Pro 6200	Iris Pro 6200	Intel HD 530	Intel HD 530	Intel HD 4600	Intel HD 4600
L3 Cache	6MB	4MB	8MB	6MB	8MB	8MB
Fabrication process	14nm	14nm	14nm	14nm	22nm	22nm
Unlocked multiplier	Yes	Yes	Yes	Yes	Yes	Yes
TDP	65W	65W	91W	91W	84W	95W

Introduction to the Skylake platform (LGA 1151)

This iteration in terms of processors and chipset (Skylake and Sunrise Point, respectively) has been one of the most anticipated in the entire history of intel, which recently came characterized by small but constant improvements but without breakthrough changes, consolidating excellent performance and consumption But without changes that supposed a real advance of the industry in the field of personal computers, as the Conroe, Nehalem or Sandy Bridge architectures could be characterized, which seem so distant today.

Make no mistake, this generation does not break with the spirit of continuity, but we must say that it brings some changes that the previous platforms were crying out for. Probably the most notable change, although not the most necessary, is the arrival in the consumption ranges of DDR4 memory, until now reserved only for an enthusiastic platform like socket 2011-3 and at really prohibitive prices.

DDR4 memory arrives on the mainstream platform

The arrival of the DDR4 should be seen more as an improvement for large servers, where you can finally go up to 1600MT / S without skipping any technology specification, and above all, we get some important improvements in consumption, since we lowered the Nominal voltage from 1.5V on DDR3 to 1.2V on DDR4, apart from other optimizations that we won't stop at. Memory has never been one of the great consumption points of a computer equipment, but now more than ever that semiconductor manufacturers have more and more problems to reduce the manufacturing process, any subsystem must be optimized.

Not everything is good things, the high frequencies of DDR4, along with the voltage drop, are charged in the form of quite high latencies, around CL12 at best, so if we look closely at this technology from the point of view of an average user, more than an improvement is a "sidegrade", since what we gain in bandwidth we lose in latencies. Equally, it is the future, and the sooner it becomes cheaper, the better for everyone. Intel has decided to integrate both memory controllers, for DDR3 and DDR4, as AMD did in its day in the transition from DDR2 to DDR3, which makes the price of chips slightly more expensive but in return should make this generation jump much more bearable.

What for me is the great improvement, which many will have already intuited when looking at the chipset diagram, is the elimination of one of the great bottlenecks that dragged the mainstream platforms since Intel divided its sockets: The shortage of pciexpress lines in the chipset part.

PCI Express lines are increased

Until now, the mainstream platforms were very limited in terms of extensibility, since the 16 pciexpress lines of the processor only added 4 by the chipset, with more latency and to top it off, the pcie2.0 revision. This was not a serious problem until now, since it was coping with the distribution in 8/8 lines for two graphics, and with bridge PLX chips in case of multigpu configurations, but it was certainly a handicap. Now, with the popularization of pciexpress and M.2 hard drives, you were forced to choose between penalizing the performance of your graphics or leaving the board without expansion options apart from that slot to make use of "only" 4 lines at 2.0 speed.

This is no longer the case, since right now the chipset has gone from having 4 pciexpress 2.0 lines to having 20 pciexpress 3.0 lines, increasing the available bandwidth by 10 times and leaving the small socket at the same level of expandability for the first time, if not better, than the X99 platform.

The rest of the changes are the usual ones in any generation. We went from 6 native USB3.0 ports on Z97 to 10 with Z170, keeping the 14 USB2.0 and 6 SATA3 ports, with slight performance optimizations as usual in these cases, but nothing big enough to force us to change.

The "up to 20" refers to the fact that the chipset's own connectivity consumes part of those pciexpress lines. For example, each occupied SATA port monopolizes one line, and each USB3 port after the sixth subtracts one more. It may seem like a bad thing, but we're certainly in much better shape than previous sockets, with all the losses benefiting chipset connectivity.

The intel RST driver continues with the same support for RAID 0, 1 and 5 for any combination of the 10 SATA ports, and adds support for RAID 0 and 1 in the SSDs corresponding to the M.2 slots, in case of having various slots.

Thanks to the extra bandwidth of the DMI3.0 connection, it is also possible to add a third graphic with these additional lines, and AMD supports 3-graphic crossfire using this configuration. NVidia, on the other hand, has preferred to opt for a policy similar to what it has carried out until now and limit the processors with 16 native lines to 2-way SLI.

The voltage regulator that was introduced with haswell again abandons the processors in this Z170 chipset, which also becomes the first in which intel fully supports overclocking, allowing among other things many multipliers that totally decouple the BCLK from the rest of buses. Gone are the days when we were almost forced to stay in the range of 90 to 110mhz for the main bus, in this image you can see an impressive 350 × 8:

We couldn't finish this introduction without mentioning the improvements that have been made to optimize energy consumption. The efficiency at full load improves only slightly what has been seen in haswell, despite the jump to 14nm, however in idle states and transitions we see a much more aggressive energy saving behavior, with additions such as completely disabling the modules in charge of executing AVX2 instructions when not in use, or new (and aggressive) hardware P-states, especially interesting for notebooks where the balance between performance and consumption is extremely delicate.

Intel Skylake i5-6600k in pictures

Intel opts for a very colorful and compact case that houses the processors that end with "K" on this new platform. It is the first time that in this range it does not incorporate the classic series fan, which has always been very useful for us to test the processor or to keep pulling.

Once we open the box we find a plastic blister that protects the processor, the warranty brochure and an adhesive sticker to stick to our tower.

The i5-6600k belongs to the Skylake family and its code name is SR2BV. Its manufacturing process is 14 nm, its die is made of a silicon surface and is 177 mm ². Although the previous series (Haswell) is less thick, we believe that this is due to the famous " delidded " to improve the temperature, so we must be careful, since it loses the guarantee if we open it.

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The Intel Core i5-6600k offers 4 cores with 4 threads of execution. It runs at a base frequency of 3.50 GHz and goes up to 3.90GHz when Turbo mode is activated. The cache memory is the same as the rest of the unlocked processor (i5-4670k and i5-4690K) with 6 MB of L3 cache memory.

The TDP already goes up to 91W and its memory controller supports both DDR3L and DDR4 RAM up to 4000 Mhz with overclock.

It incorporates MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, EM64T, VT-x, AES, AVX, AVX2, FMA3 and TSX instructions. The integrated graphics card that it incorporates is the Intel HD Graphics 530 with 48 execute Units, this implies a great improvement over the HD4600 series with almost double the performance and is more powerful than the latest generation AMD APUs.

Test bench and performance tests

TESTING BENCH
Processor	Intel i5-6600k
Base plate	Asus Maximus VIII Hero
RAM	Kingston Savage DDR4 @ 3000 Mhz.
Heatsink	Corsair H100i GTX.
HDD	Samsumg 850 EVO.
Graphic card	GTX980 Ti 6GB stock
Power supply	Antec HCP 850.

To check the stability of the processor we have used a very efficient motherboard in consumption / cooling. We have practiced a strong overclock of 4600 mhz with Prime 95 Custom, reaching the limit of air cooling. The graphic that we have used is TOP RANGE: Asus GTX 980 Ti.

Without further delay we present the results obtained in our laboratory:

Benchmark in Games

We have compared it to its older brother the i7-6700k and the differences hardly compensate for acquiring the superior model. The i5 defends itself in all games and is capable of holding two graphics cards at full load.

Overclocking

The i5-6600k has been able to go up to a more than interesting 4, 600 Mhz with a voltage of 1.32v (not tuned). I was able to increase its power to 4.7 Ghz but the temperatures and voltage were too high.

As you can see the following table, the performance is quite relevant.

Temperatures and consumption

To test the real performance of the heatsink we are going to stress the best processors on the market: Intel Skylake i5-6600k. Our tests consist of 72 uninterrupted hours of work. In stock values ​​and with overclocked 4600 mhz. In this way we can observe the highest temperature peaks and the average that the heatsink reaches. We must bear in mind that when playing or using other types of software, temperatures will drop dramatically between 7 to 12ºC.

How are we going to measure the processor temperature?

We will use the internal sensors of the processor. For that test on Intel processors we will use the CPUID HwMonitor application in its latest version. Although it is not the most reliable test of the moment, it will be our reference in all our analyzes. The ambient temperature is 20º.

Let's see the results obtained:

Final words and conclusion

Intel has built one of the best quality / price processors on the market. The Intel Core i5 6600k offers a speed of up to 3.9 GHz, 4 cores, 6 MB of cache and a 14 nm manufacturing process.

In our tests we have been able to verify that the performance with its big brother the i7-6700k is not as distant as the price that each of them can acquire. For example, in games we have obtained results of 220 FPS with Tomb Raider in 1920 x 1080 resolution with a GTX 980 Ti. It has also allowed us to overclock 4600 Mhz with a voltage of 1.32v.

In short, if you are looking for an off-road processor without going over 250 euros, the i5 6600k is your best option both for performance, overclock and temperatures.

ADVANTAGE	DISADVANTAGES
+ POWER	- DOES NOT INCLUDE HEATSINK
+ VERY GOOD TEMPERATURES
+ LOW CONSUMPTION
+ GAME PERFORMANCE
+ VERY GOOD OVERCLOCK

The Professional Review team awards you the Platinum medal and the recommended product insignia:

Intel Core i5-6600k

YIELD ONE WIRE

MULTI-THREAD PERFORMANCE

OVERCLOCK

PRICE

9.2 / 10

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