Intel Core i7-4578U vs Intel Core i7-7700T vs Intel Core i7-4870HQ

The Intel Core i7-4578U is a LV (low voltage) dual-core processor for large ultrabooks launched in Q3/2014. It is based on the Haswell architecture and is manufactured in 22nm. Due to Hyper-Threading, the two cores can handle up to four 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 3.5 GHz.

Architecture

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, improving the performance per clock by almost 10 percent. Furthermore, new features like AVX2 and FMA should increase the performance in future applications.

Performance

The performance of the Core i7-4578U is slightly above the older and somewhat higher clocked Core i7-3540M. However, when using new instruction sets such as AVX2 the performance can be significantly better. Thus, the CPU has sufficient power for office and multimedia purposes as well as more demanding applications.

Graphics

The integrated Iris Graphics 5100 offers 40 Execution Units (EUs) clocked at 200 - 1200 MHz with Turbo Boost, making it significantly faster than the HD Graphics 4000. As a result, the Iris Graphics competes with dedicated lower mid-range graphics cards (e.g. GeForce GT 720M).

Power Consumption

The i7-4578U is rated at a TDP of 28 W including the graphics card, memory controller, VRMs and the integrated chipset. Therefore, the CPU is suited for larger, well-cooled ultrabooks.

The Intel Core i7-4870HQ is a high-end quad-core processor for laptops launched in Q3 2014. It is based on the Haswell architecture and manufactured in 22nm. 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 2.5 GHz but can dynamically increase clock rates with Turbo Boost up to 3.5 GHz (for 4 active cores), 3.6 GHz (for 2 active cores) and 3.7 GHz (for 1 active core). A noteworthy feature is the fast integrated graphics unit (GT3e) with eDRAM memory (128 MB, 77 mm², on-package, 102 GB/s).

Architecture

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, improving the performance per clock by 5 - 10 percent. Furthermore, new features like AVX2 and FMA should increase the performance in future applications.

Performance

Compared to the Core i7-4860HQ, the 4870HQ is clocked just 100 MHz higher and therefore only slightly faster. Overall, the performance is similar to the Ivy Bridge-based Core i7-3920XM. Even extremly demanding software or multitasking will be handled easily.

Graphics

The integrated Iris Pro Graphics 5200 GPU offers 40 Execution Units (EUs) clocked at 200 - 1200 MHz (Turbo clock not confirmed yet), making it significantly faster than the HD 4000 or HD 4600. The additional eDRAM memory further improves performance. As a result, the HD 5200 competes with dedicated mid-range graphics cards like the GeForce GT 740M.

Power Consumption

The i7-4870HQ is rated at a TDP of 47 W including the integrated graphics card, memory controller and VRMs.  Therefore, the CPU is best suited for laptops 15-inches or greater.