Intel Core i7-740QM vs Intel Core i7-840QM
Intel Core i7-740QM► remove
The Intel Core i7-740QM is a fast quad-core CPU for laptops. Compared to the Core i7-720QM, the 740QM features a higher clock rate. It features 4 cores and Hyperthreading. Therefore, 8 threads can be worked on simultaneously. Compared to the faster Core i7 mobile CPUs, the 740QM only features 6MB L3 Cache (the faster ones 8 MB).
Because of the Turbo Mode, the CPU can be clocked with up to 2.93 GHz (1 core only) and therefore fast for single core applications like older games. Thanks to the 4 cores (and 8 threads), modern multi-threaded applications also profit from this CPU greatly (altough when using all cores, the clock speed remains low).
The Core i7 7xx line has an integrated memory controller for DDR3 bars (1066 or 1333). Therefore, the memory performance is very good (compared to older CPUs with external memory controllers). Still this also leads to the higher TDP of the whole chip.
The performance depends on the used thread count. If all cores are fully used, the performance of the 740QM is on a level with the fast Core i5-2520M (Sandy Bridge). If only a single core / thread is fully used, the performance depends on the Turbo Boost. Benchmarks indicate a performance on a level of the Core i5-480M.
The power consumption of up to 45 Watt (TDP) is quite high for a laptop CPU and because of the Turbo Mode, the power consumption could reach these high values. Therefore, only large laptops with good cooling solutions can house this CPU.
Intel Core i7-840QM► remove
The Intel Core i7 840QM is a high end quad core CPU in 2010. It features 4 cores (quad core CPU) and Hyperthreading. Therefore, 8 threads can be worked on simultaneously.
Because of the Turbo Mode, the CPU is clocked with up to 3.2 GHz (if only one core is used, 2.93 for two cores, and 2 ghz with 4 cores) and therefore can perform very well in single core applications like older games.
The Core i7 line has an integrated memory controller for DDR3 bars (1066 or 1333) supporting a maximum of 8 GB. Therefore, the memory performance is very good (compared to older CPUs with external memory controllers). Still, this also leads to the higher TDP of the whole chip. ECC memory is not supported by the 840QM.
The Core micro-architecture is still very similar to the one used in the Core 2 CPUs, therefore the performance per MHz (neglecting the integrated memory controller, hyperthreading and Turbo Boost) is similar.
The power consumption of up to 45 Watt (TDP) is quite high for a laptop CPU and because of the Turbo Mode, the power consumption should reach these high values. Therefore, the CPU is only suited for large laptops.
|Intel Core i7-740QM||Intel Core i7-840QM|
|Intel Core i7||Intel Core i7|
|: Core i7 Clarksfield|
|1730 - 2930 MHz||1860 - 3200 MHz|
|256 KB||256 KB|
|1 MB||1 MB|
|6 MB||8 MB|
|4 / 8||4 / 8|
|296 mm2||296 mm2|
|100 °C||100 °C|
|Turbo Boost max. 2.93GHz||integrated DDR3-1066/1333 dual-channel memory controller, Turbo Boost, Hyper Threading, Virtualization Technology VT-x / VT-d, Trusted Execution Technology, Intel 64, Idel States, Enhanced Speedstep, Thermal Monitoring, Execute Disable Bit|
|$546 U.S.||$568 U.S.|
|Intel Core i7 740QM||Intel Core i7 840QM|