Intel Core i7-7500U vs Intel Core i7-3540M vs Intel Celeron 3965U

Intel Core i7-7500U

The Intel Core i7-7500U is a dual-core processor of the Kaby Lake architecture. It offers two CPU cores clocked at 2.7 - 3.5 GHz and integrates HyperThreading to work with up to 4 threads at once. The architectural differences are rather small compared to the Skylake generation, therefore the performance per MHz is very similar. The SoC includes a dual channel DDR4 memory controller and Intel HD Graphics 620 graphics card (clocked at 300 - 1050 MHz). It is manufactured in an improved 14nm FinFET process (14nm+) at Intel. Compared to the old Skylake Core i7-6500U (2.5 - 3.1 GHz), the i7-7500U clock speed is up to 400 MHz higher.

Intel Core i7-3540M

The Intel Core i7-3540M is the fastest dual-core 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 3.0 GHz but can dynamically increase clock rates with Turbo Boost up to 3.5 GHz (for 2 active cores) and 3.7 GHz (for 1 active core). As its Sandy-Bridge-based predecessor Core i7-2640M, 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 i7-3540M is slightly above a similarly clocked Sandy Bridge processor due to the architectural improvements. As a result, overall performance is about 5 - 10 % above the old i7-2640M.

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 fastest variants.

Just like most other Ivy Bridge dual-cores, the i7-3540M is rated at a TDP of 35 W. Therefore, even smaller laptops can use the Core i7.

Intel Celeron 3965U

The Intel Celeron 3965U is an ULV (ultra low voltage) dual-core SoC based on the Kaby-Lake architecture and has been launched in the first quarter of 2017. The CPU can be found in ultrabooks as well as normal notebooks. In addition to two CPU cores without Hyper-Threading clocked at 2.2 GHz (no Turbo Boost), the chip also integrates an HD Graphics 610 GPU and a dual-channel DDR4-2133/DDR3L-1600 memory controller. The SoC is manufactured using a 14 nm process with FinFET transistors.

Architecture

Intel basically uses the same micro architecture compared to Skylake, so the per-MHz performance does not differ. The manufacturer only reworked the Speed Shift technology for faster dynamic adjustments of voltages and clocks, and the improved 14nm process allows much higher frequencies combined with better efficiency than before.

Performance

Due to the missing Turbo Boost and the low clock speeds, especially the single thread performance is very limited which results in a lower performance even for lower demanding tasks. The performance should be between the Intel Pentium 4405U and 4415U. Still, the CPU has sufficient power for office and multimedia purposes.

Graphics

The integrated graphics unit called HD Graphics 610 (similar to the HD Graphics 510) represents the "GT1" version of the Kaby Lake GPU (Intel Gen. 9). Its 12 Execution Units, also called EUs, are clocked at 300 - 900 MHz and offer a performance somewhat below the older HD Graphics 4400. Only a few games of 2015 can be played smoothly in lowest settings.

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 10 watts (cTDP down), reducing both heat dissipation and performance and allowing even more compact designs.