Intel Core i7-6600U vs Intel Core i7-4550U vs Intel Core i7-6870HQ

Intel Core i7-6600U

The Intel Core i7-6600U is an ULV (ultra low voltage) dual-core SoC based on the Skylake architecture. In September 2015, it's the fastest CPU of the 15 W series, which can be found in ultrabooks as well as normal notebooks. In addition to two CPU cores with Hyper-Threading clocked at 2.6 - 3.4 GHz (2 cores: max. 3.2 GHz), the chip also integrates an HD Graphics 520 GPU and a dual-channel DDR4-2133/DDR3L-1600 memory controller. The SoC is manufactured using a 14 nm process with FinFET transistors.

Architecture

Skylake replaces both Haswell and Broadwell and brings the same microarchitecture in every TDP class from 4.5 to 45 W. The extensive improvements of the Skylake design include increased out-of-order buffers, optimized prefetching and branch prediction as well as additional performance gains through Hyper-Threading. Overall, however, performance per clock has been increased by only 5 to 10 percent (compared to Haswell) respectively under 5 percent (compard to Broadwell), which is quite modest for a new architecture ("Tock").

Performance

According to the specified clock rates and the improved architecture, the Core i7-6600U should perform similar to a Core i5-4310M (Haswell, 37 W) and is one of the fastest ULV dual-cores as of late 2015. Thus, the CPU has sufficient power for office and multimedia purposes as well as more demanding applications and multitasking.

Graphics

The integrated graphics unit called HD Graphics 520 represents the "GT2" version of the Skylake GPU (Intel Gen. 9). The 24 Execution Units, also called EUs, are clocked at 300 - 1050 MHz and offer a performance somewhere in range of a dedicated GeForce 820M. Games of 2015 can thus be played smoothly in low settings. For more information about performance and features, check our page for the HD Graphics 520.

Power Consumption

Specified at a TDP of 15 W (including CPU, GPU and memory controller), the CPU is best suited for small notebooks and ultrabooks (11-inches and above). Optionally, the TDP can be lowered to 7.5 watts (cTDP down), reducing both heat dissipation and performance and allowing even more compact designs.

Intel Core i7-4550U

Intel Core i7-6870HQ

The Intel Core i7-6870HQ is a fast quad-core processor for notebooks based on the Skylake architecture and was introduced in the beginning of 2016. Besides four CPU cores including Hyperthreading, which are clocked between 2.7-3.6 GHz (probable Turbo steps: 4 cores: up to 3.2 GHz, 2 cores: up to 3.4 GHz), the processor also includes a very fast graphics unit. The Iris Pro Graphics 580 (GT4e) has 72 EUs as well as 128 MB eDRAM cache, which can also be used by the CPU cores. It is manufactured using a 14 nm process with FinFET transistors.

Contrary to other models like the Core i7-6820HQ, the i7-6870HQ does have a much faster GPU, but neither supports the instruction set extensions TSX-NI nor vPro.

Architecture

Intel uses Skylake to replace both Broadwell as well as Haswell and therefore uses one core design for all TDP classes between 4.5-45 Watts. Several improvements of the Skylake architecture include bigger Out-to-Order-Buffer, optimizations for pre-fetching as well as bigger gains by Hyperthreading. However, the changes are small for a "Tock" – a new micro architecture – in general, so the per-MHz performance is only between 5-10 % (compared to Haswell) or less than 5 % higher (compared to Broadwell), respectively.

The i7-6870HQ also benefits from the additional eDRAM cache in some cases, which can accelerate memory-heavy applications in particular.

Performance

Thanks to the additional eDRAM cache, the i7-6870HQ should even compete with the similarly clocked i7-6820HQ and is therefore one of the fastest notebook processors in the beginning of 2016. Even the most demanding applications and excessive multi-tasking are no problem for the high-end CPU.

Graphics

The integrated GPU with the designation Iris Pro Graphics 580 (also known as "GT4e") represents the fastest version of the Skylake GPU (Intel Gen. 9). 72 Execution Units (EUs) run at 350 up to 1000 MHz and allow a performance comparable to a dedicated mainstream chip. The GPU might be able to compete with a GeForce 945M under perfect conditions and it is therefore the fastest iGPU on the market by a pretty big margin. Modern games from 2015/2016 can usually be played smoothly at medium settings. More information about the performance and the features is available on our dedicated page for the Iris Pro Graphics 580.

Power Consumption

According to its TDP of 45 Watts, the chip is primarily designed for bigger notebooks starting with 15-inch screens. The TDP can optionally be reduced to 35 Watts (cTDP down), but this would obviously affect the performance.