Intel Core i7-2640M vs Intel Core i7-2657M vs Intel Core i7-2675QM

Intel Core i7-2640M

The Intel Core i7-2640M is the fastest dual core processor at the time of introduction in Q3 2011 and successor of the slower clocked i7-2620M. It is based on the Sandy Bridge architecture and offers Hyperthreading to handle 4 threads at once (for a better usage of the pipeline). Compared to the slower Core i5, the i7 offers a larger last level cache of 4MB. The base clock speed is 2.8 GHz but due to Turbo Boost it can reach 3.3 GHz (2 cores active) and 3.5 GHz (1 core active).

The 35W TDP rating includes the integrated GPU and memory controller.

Intel Core i7-2657M

The Intel Core i7-2657M is power efficient ULV (Ultra Low Voltage) processor for thin and light laptops. The base frequency of 1.6 GHz is relatively low, but due to Turbo Boost 2.0, the CPU may clock up to 2.7 GHz (on core loaded, 2.4 GHz with both cores loaded). However, this depends on the cooling and power consumption of the laptop. Due to HyperThreading, the i7-2657M is able to handle 4 threads in parallel. Compared to the slower i7-2617M, the 2657M offers a higher clock speed (processor core and turbo, graphics turbo).

Sandy Bridge is the evolutionary successor of the Arrandale architecture. The most noteable improvements is the improved Turbo 2.0 and the integration of the graphics card into the 32nm CPU core. 

The integrated Intel HD Graphics 3000 clocked at 350 or 1000MHz (Turbo Boost). Due to the slower clock rate, compared to HD Graphics 3000 in 35W and 45W processors (usually clocked at 650-1100/1300MHz in non LV processors), the performance should be noticeable lower.

The performance of the CPU should be a bit higher than a similar clocked Arrandale Core i5. In our benchmarks (see below), the ULV processor was as fast as a Core i3-2310M due to the high Turbo Boost frequencies. However, the laptop cooling system has to keep the processor relatively cool for the Turbo Boost to work often.

The TDP of 17W (includes the integrated GPU and memory controller) allows the use of the 2657M CPU in small subnotebooks.

Intel Core i7-2675QM

The Intel Core i7-2675QM is a fast quad core processor for laptops and successor to the popular i7-2630QM. It is based on the Sandy Bridge architecture and offers Hyperthreading to handle 8 threads at once (for a better usage of the pipeline). Compared to the 2630QM, the 2675QM offers higher base and turbo frequencies by 200MHz. Compared to the faster Core i7, the 2675QM does not feature the Trusted Execution and the VT-d functions.

Sandy Bridge is the evolutionary successor of the Arrandale architecture. The most noteable improvements are the new 265Bit AVX instructions, the improved Turbo 2.0 and the integration of the graphics card into the 32nm CPU core. 

Der i7-2630QM offers an integrated graphics card (Intel HD Graphics 3000) which is clearly faster then the older Intel HD Graphics in the Arrandale CPUs. As the new GPU is included in the CPU, it is also manufactured in 32nm and shares the fast level 3 cache with the CPU cores (using a new ring bus). In the 2635QM it is clocked from  650-1200MHz (Turbo Boost). The Core i7-2630QM in comparison offers a lower Turbo Boost frequency of 1100MHz for the GPU part.

Furthermore, an improved (compared to Clarkdale) dual-channel DDR3 memory controller is included on the CPU die that is used by the CPU and GPU part.

The performance of the Core i7-2675QM should be only slightly slower than the old Core i7-2720QM that offers only a slightly higher Turbo Boost frequencies. Therefore, even demanding applications and games should run without performance problems.

The quad core CPU is still rated at 45 Watt TDP but now the integrated graphics card is also included (compared to the old Clarksfield Quad Core processors).