Announces at the opening of the Computex exhibition their new Broadwell processors in the LGA1150 version for desktop systems, Intel promised that they will be available in open sale within 30-60 days. This has convinced many that the release has all the signs of a “paper” and real appearance of desktop Broadwell on the shelves of stores will have to wait until the second half of the summer. However, the reality tells us that Intel, when voicing the terms, was simply reinsured and in fact delivering desktop Broadwell to retail networks has already begun. Yes, there are not so many processors, and the company is afraid that it will not be able to provide all the newcomers with novelties, however, having some luck, it is quite possible to find them in the retail sale.
Of course, this does not mean there is a wide range of new 14-nm chips in stores. But this is due not to their acute deficit, but to the fact that the lineup of novelties, if not formally taking into account the server modifications of Xeon E3 v4, is limited to only two options – Core i7-5775C and Core i5-5675C. Intel simply did not make the line of desktop Broadwell wide and diverse, and it reflects its essence – the new processors are not a replacement and full-fledged heirs of Haswell. As we demonstrated in our initial review of Broadwell in LGA1150-performance, it is more correct to consider the novelty not as a habitual solution for productive computers, but as a rather fast, but energy-efficient processor with a powerful graphics core, which is most suitable for use in systems of compact form factors.
However, in the last review we tested the Xeon E3-1285 v4, and although it is similar to the Core i7-5775C, in fact it is still different. Oriented for use in workstations, Xeon E3 v4 is more expensive and does not support overclocking, which means it is impossible to fully appreciate all the pros and cons of the new processor design. That is why, developing the topic we raised earlier, we turn to the reviews of these desktop Broadwell – today we will talk about the Core i5-5675C. We decided to start with this modification because it differs the most from the previously reviewed Xeon E3-1285 v4 in terms of performance and is also the cheapest 14-nm processor in LGA1150-performance. Officially, the Core i5-5675C is priced at $ 276, which makes this model quite an acceptable option both for conventional desktop systems with a total cost of about $ 800, and for cheaper computers without a discrete graphics card.
⇡ # Read more about Core i5-5675C
The architecture and features of Broadwell’s new processor design were described in detail in our previous review, so here we will only focus on the features specific to the Core i5-5675C.
Traditionally, the desktop processors of the Core i5 series differed from their older counterparts in three ways. First, although they had four full-fledged computing cores, Hyper-Threading was deactivated in them, which reduced the number of concurrently executing threads from eight to four. Second, in Core i5, the third-level cache memory was 25% smaller than in Core i7, the size. And thirdly, the Core i5 processors had lower clock speeds. All these three features are also characteristic of Core i5-5675C. It has four cores, but does not support Hyper-Threading; its L3-cache is 2 MB less than the Core i7-5775C; is noticeably lower than that of the older model, and the clock frequency.
However, since the Core i5-5675C belongs to the Broadwell generation, there are some features in its characteristics. For example, while the Core i5 of previous generations had a 6MB L3 cache, the new processor cut it to 4MB, that is, to the size that is characteristic of the older dual-core Haswell. Became below the usual values and clock speeds: before the nominal frequency of older Core i5 was always in the range 3.3-3.5 GHz, while the Core i5-5675C had a passport frequency of only 3.1 GHz. This deterioration in the basic specifications can be perceived as a reflection of Intel’s problems with the 14-nm process and the payment for the appearance in the processor of a powerful graphics core Iris Pro 6200 with 48 executive devices. But in many respects thanks to this, the calculated heat dissipation of the Core i5-5675C was reduced from the usual 84-88 W to 65 W, and in this sense the novelty is an economical rather than a productive processor.
As a result, the final characteristics of the Core i5-5675C look like this:
Please note: the screenshot shows a 3.5 GHz processor frequency, and this is a manifestation of Turbo Boost technology. With a load of three or four cores, the processor can actually automatically accelerate to 3.5 GHz, and if the work falls on one or two cores – the frequency can reach up to 3.6 GHz. Thus, the turbo mode of the Core i5-5675C behaves slightly more aggressively than the predecessors of the Haswell generation. But in the case of Broadwell, its limitations imply a 65-watt thermal package, and with a high load on the processor cores, the frequency does not necessarily reach the maximum possible: in order not to go beyond the established limits for heat generation and power consumption, the Core i5-5675C can decelerate to 3.1-3 , 3 GHz. In other words, its behavior in real conditions is more typical for the mobile than for the desktop CPU.
Another feature of desktop Broadwell has not disappeared: Core i5-5675C is equipped with an additional chip Cristalwell, which plays the role of cache memory of the fourth level. This cache, made in the form of an additional eDRAM chip hidden under the cover of the processor, as well as in older models, has a capacity of 128 MB and operates at a frequency of 1.6 GHz. On the speed of such a solution, you can get an idea, for example, based on the results of the Cache and Memory Benchmark from the AIDA64 utility.
As Intel limited its heat dissipation to 65W for its desktop 14nm processors, the Core i5-5675C has a relatively low operating voltage. For example, our processor instance worked at 1.15 V. However, multi-core Haswell-E processors use even lower voltage, so this is not a record. Broadwell, however, is characterized by the fact that the integrated power converter of these processors provides very good voltage stability. Regardless of the load growth and the Turbo Boost technology, in most cases the voltage remains constant.
It should be recalled that Core i5-5675C is not considered by Intel as a replacement for Core i5-4690K. Both these models will co-exist in parallel. While the Core i5-4690K will still be oriented to traditional desktop systems, the Core i5-5675C will act as a processor designed primarily for miniature systems, monoblocks and configurations such as Steam Machines. The fact that Core i5-5675C and Core i5-4690K are birds of different flight can be clearly seen from the following table, in which we compared the characteristics of these solutions.
|Core i5-5675C||Core i5-4690K|
|The code name of the||Broadwell-C||Haswell Refresh|
|Nuclei / flows||4/4||4/4|
|The technology of Hyper-Threading||No||No|
|The clock speed||3.1 GHz||3.5 GHz|
|The maximum frequency in the turbo mode||3.6 GHz||3.9 GHz|
|The unlocked multiplier||There are||There are|
|TDP||65 W||88 W|
|HD Graphics||Iris Pro 6200||HD Graphics 4600|
|The frequency of the graphic core||1100 MHz||1200 MHz|
|L3-cache||4 MB||6 Mbyte|
|Integrated eDRAM||128 MB||No|
|Support for DDR3||1333/1600||1333/1600|
|Technologies vPro / TSX-NI / TXT / VT-d||TSX-NI and VT-d||TSX-NI and VT-d|
|Extensions of the instruction set||AVX 2.0||AVX 2.0|
|The recommended price||$ 276||$ 242|
The fact that the Core i5-5675C is based on a new version of the Intel Core microarchitecture should be added to the data in the table. However, since Broadwell belongs to the development phase of “tick”, there are few deep changes in it, the main thing in this design is the transition to the technological process with 14-nm standards and second-generation FinFET transistors. Intel itself believes that at the same frequency Broadwell cores win Haswell in performance up to 5 percent, but in the past testing even such a modest estimate seemed too optimistic. More cardinal improvements at the level of microarchitecture will be implemented in the promising Skylake processors, which should be launched in a few months. However, they will require the transition to a new platform – LGA1151.
As for desktop Broadwell in general and Core i5-5675C in particular, these processors are compatible with the already existing LGA1150-ecosystem. For them, any motherboards based on Intel Z97 / H97 logic chipsets with an updated BIOS are suitable. But the motherboards of the previous generation, based on Intel Z87 / H87 / B85 chipsets and the like, with Broadwell, most likely will not work.
⇡ # Dispersal
Overclocking desktop processors Broadwell remains one of the most intriguing topics. The new technological process with 14-nm standards and lower heat generation Core i5-5675C initially inspired the hope that the frequency potential of this processor will be at least as good as that of Devil’s Canyon. However, until now, there has been no confirmation of this, and it’s no accident – as demonstrated by the test, when overclocking the Core i5-5675C there are significant problems.
Formally Intel classifies this CPU as an overclocker, and it does not really fix any multiplication factors, which allows to increase the frequency of both processor cores, memory or GPU. However, the thermal package limited by the 65-Watt frames does not help the normal overclocking, but on the contrary it hinders. The fact that the class of energy-efficient processors Core i5-5675C interactively controls the power consumption. And as soon as it goes beyond the acceptable limits, its multiplier is automatically reset to the nominal value, returning the processor frequency to 3.1 GHz.
This behavior is not the result of temperature trotting. The desktop Broadwell processors can operate at temperatures up to 96 degrees, and forced frequency reduction occurs with much less heat. In fact, we are talking about the automatic shutdown of Turbo Boost technology, through which any increase in the frequency of the processor is realized, if the power levels set up with a view to energy efficiency are exceeded, passing through the integrated power regulator in the CPU. By the way, the described protection mechanism can be observed in the Core i5-5675C and without overclocking: the turbo mode at high load can be periodically deactivated, but when the processor is used in the normal mode, this is almost imperceptible. Much worse is that such intrusive “overload protection” remains active even if the processor is overclocked, which almost eliminates any attempt to increase the frequency, especially if it is accompanied by a change in the supply voltage.
Fortunately, Broadwell’s commitment to maintaining low energy consumption is not a verdict. Some motherboard manufacturers were able to circumvent this protection by deliberately distorting the information received by the processor about its energy state. In ASUS boards, where we usually conduct our overclocking experiments, two UEFI options – Power Current Slope and Power Current Offset – are located in the CPU Internal Power Configuration section. By changing the value of these parameters as indicated in the screenshot below, you can ensure that the processor does not reset the frequency.
However, do not think that a victory over the protective mechanism of Core i5-5675C means the opportunity to achieve stable operation at striking frequencies. Intel in its materials indicates that the average overclock for the processors Core i7-5775C and Core i5-5675C, achievable with air cooling, is only 4.2 GHz. Broadwell’s design is completely not aimed at conquering high clock speeds, its main goal is energy efficiency. In addition, we should not forget about Intel’s problems with the introduction of 14-nm process technology, which also limited the overclocking potential of new products. Therefore, in general, there is nothing surprising in the fact that Broadwell accelerates worse than their predecessors.
Everything we said in the previous paragraph can be confirmed by the results of our own tests. With a rather efficient air cooler Noctua NH-U14S, the test Core i5-5675C was able to demonstrate stable operation only at frequencies up to 4.2 GHz. The supply voltage in this case had to be increased to 1.3 V.
In this state, the maximum temperature of the processor did not exceed 89 degrees. Further overclocking rested precisely in overheating. An increase in the frequency to 4.3 GHz required an additional increase in the supply voltage, and in the aggregate this led to the fact that the temperature crossed the 96-pile border, after which Broadwell switched on temperature throttling. Therefore, a 35 percent increase in the frequency (up to 4.2 GHz) had to stop. In the end, it’s not such a bad result.
It should be added that if you use a more efficient cooling system or scalp the processor to remove heat, replacing the polymer thermo-interface material located underneath its cover with a more efficient thermal paste, you probably can expect better from Core i5-5675C ( per 100 -200 MHz ) overclocking. However, today we will refrain from such experiments, because it still will not affect the main conclusion: desktop Broadwell accelerates significantly worse than its 22-nm predecessors of the Devil’s Canyon series, with which frequencies of about 4.5 GHz are achievable without any tricks. Well, the leaders in absolute overclocking among all the Core processors remain, as ironically as possible, representatives of the Sandy Bridge generation. Yet subsequent improvements to Intel’s processor design have only worsened the overclocking potential, and Broadwell continues this sad trend.