Intel Core i7-4900MQ vs Intel Core i7-4558U

The Intel Core i7-4900MQ is a high-end quad-core processor for laptops which has been launched in Q2/2013. 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 2.8 GHz but can dynamically increase clock rates with Turbo Boost up to 3.6 GHz (for 4 active cores), 3.7 GHz (for 2 active cores) and 3.8 GHz (for 1 active core).

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.

Due to these changes, the overall performance has been improved slightly compared to Ivy Bridge. Therefore, the 4900MQ is about 10 % faster than the former i7-3840QM.

The integrated Intel HD Graphics 4600 offers 20 Execution Units (EUs) clocked at 400 MHz up to 1300 MHz with Turbo Boost, making it about 30 % faster than the HD 4000.

The i7-4900MQ is rated at a TDP of 47 W including graphics card, memory controller and VRMs.  Therefore, the CPU is only suited for laptops 15-inches or greater.

The Intel Core i7-4558U is a LV (low voltage) dual-core processor for large ultrabooks launched in Q2 2013. 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 2.8 GHz, but can dynamically increase clock rates with Turbo Boost up to 3.3 GHz for 1 active core or 3.2 GHz for 2 active cores.

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.

The performance of the Core i7-4558U is slightly above the older and somewhat higher clocked Core i7-3520M. 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.

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.

The i7-4558U 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 ultrabooks 14-inches or greater.