Intel Core i7-4578U vs Intel Core i7-7820HQ vs Intel Core i7-4930MX

Intel Core i7-4578U

Intel Core i7-7820HQ

The Intel Core i7-7820HQ is a fast quad-core processor for notebooks based on the Kaby Lake architecture and was announced in January 2017. It is the second fastest model of the consumer series at the time of the announcement. Only the i7-7920HQ and Xeon E3-1535M v6 are faster. Besides four cores including Hyper-Threading support running at 2.9 - 3.9 GHz (4 cores up to 3.5 GHz, 2 cores up to 3.7 GHz), the processor is also equipped with the HD Graphics 630 GPU as well as a dual-channel memory controller (DDR3L-1600/DDR4-2400). It is manufactured in a 14nm process with FinFET transistors.

Architecture

Intel basically uses the same micro architecture compared to Skylake, so the per-MHz performance does not differ. The manufacturer only reworked the Speed Shift technology for faster dynamic adjustments of voltages and clocks, and the improved 14nm process allows much higher frequencies combined with better efficiency than before.

Performance

Due to the higher clock speeds, the performance of the i7-7820HQ is slightly faster than the old Skylake top model Core i7-6920HQ (2.9 - 3.8 GHz). The performance is sufficient even for very demanding tasks and on par with powerful desktop quad-core processors.

Graphics

The integrated Intel HD Graphics 630 has 24 Execution Units (similar to previous HD Graphics 530) running at 350 - 1100 MHz. The performance depends a lot on the memory configuration; it should be comparable to a dedicated Nvidia GeForce 920M in combination with fast DDR4-2133 dual-channel memory.

Contrary to Skylake, Kaby Lake now supports hardware decoding for H.265/HEVC Main 10 with a 10-bit color depth as well as Google's VP9 codec. The dual-core Kaby Lake processors, which were announced in January, should also support HDCP 2.2.

Power Consumption

The chip is manufactured in an improved 14nm process with FinFET transistors, which improves the efficiency even further. Intel still specifies the TDP with 45 Watts, but it can also be reduced to 35 Watts by the notebook manufacturers (cTDP down). This will obviously affect the performance, because the Turbo Boost cannot be maintained for longer periods.

Intel Core i7-4930MX

The Intel Core i7-4930MX is a high-end quad-core processor for laptops and successor of the i7-3940XM. It is based on the Haswell architecture and was launched in Q2/2013. Due to Hyperthreading, the four cores can handle up to eight threads in parallel leading to better utilization of the CPU. Each core offers a base speed of 3.0 GHz but can dynamically increase clock rates with Turbo Boost up to 3.7 GHz (for 4 active cores), 3.8 GHz (for 2 active cores) and 3.9 GHz (for 1 active core). Furthermore, the Extreme CPUs offer an unlocked multiplicator for easy overclocking.

Haswell is the successor to the Ivy Bridge architecture with improvements on both GPU and CPU performance. The CPUs are produced in 22nm and offer an optimized branch prediction as well as additional execution ports. Furthermore, new features like AVX2 and FMA should increase the performance in future applications.

Due to these changes, the performance per clock has been improved by about 10 percent compared to Ivy Bridge. Therefore, the 4930MX is almost 10 % faster than the former i7-3940XM.

The integrated Intel HD Graphics 4600 offers 20 Execution Units (EUs) clocked at 400 MHz up to 1350 MHz with Turbo Boost, making it about 30 % faster than the HD 4000.

The i7-4930MX is rated at a TDP of 57 W including graphics card, memory controller and VRMs.  Therefore, the CPU is only suited for laptops 17-inches or greater.