Intel Core i7-840QM vs Intel Core i7-3687U vs Intel Core i7-3840QM

Intel Core i7-840QM

Intel Core i7-3687U

The Intel Core i7-3687U is the fastest ULV-processor for laptops based on the Ivy Bridge architecture at the time of introduction in Q1 2013. Due to Hyperthreading, 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 2.1 GHz but can dynamically increase clock rates with Turbo Boost up to 3.1 GHz (for 2 active cores) and 3.3 GHz (for 1 active core). As its Sandy-Bridge-based predecessors, it offers a 4 MB L3-Cache.

Ivy Bridge is an enhanced die shrink of the Sandy Bridge architecture with improvements on both GPU and CPU performance. The CPUs are produced in 22nm (versus 32nm Sandy Bridge CPUs) and are the first to introduce 3D transistors for increased energy efficiency when compared to similarly clocked Sandy Bridge processors. Other new features are integrated PCI Express 3.0 and  DDR3(L)-1600 support.

The performance of the Core i7-3687U is slightly above a similarly clocked Sandy Bridge processor due to the architectural improvements. Therefore, and because of the higher clock speed, the old Core i7-2677M is easily outperformed.

The integrated Intel HD Graphics 4000 offers 16 Execution Units (EUs) clocked at 350 MHz up to 1200 MHz with Turbo Boost, delivering a performance comparable with an AMD Radeon HD 6620G.

The ULV-CPUs are rated at a TDP of 17 W including graphics card and memory controller.  Therefore, the CPU is suited for small laptops and ultrabooks.

Intel Core i7-3840QM

The Intel Core i7-3840QM is a fast quad-core processor for laptops based on the Ivy Bridge architecture and successor of the i7-3820QM. 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). Furthermore, the CPU offers 8 MB Last Level 3 Cache.

Ivy Bridge is an enhanced die shrink of the Sandy Bridge architecture with improvements on both GPU and CPU performance. The CPUs are produced in 22nm (versus 32nm Sandy Bridge CPUs) and are the first to introduce 3D transistors for increased energy efficiency when compared to similarly clocked Sandy Bridge processors. Other new features are integrated PCI Express 3.0 and  DDR3(L)-1600 support.

The performance of the Core i7-3840QM should be slightly above a similarly clocked Sandy Bridge processor due to slight architectural improvements. Overall, performance should be similar to the Core i7-3920XM.

The integrated Intel HD Graphics 4000 offers 16 Execution Units (EUs) clocked at 650 MHz up to 1300 MHz with Turbo Boost, making it one of the faster variants.

As with most quad-core Ivy Bridge models, the Core i7-3840QM is specified at a TDP of 45 Watts including graphics card and memory controller. Therefore, the CPU is well-suited for laptops 15-inches or greater.