Intel Core i5-540M vs Intel Core i7-1355U

Intel Core i5-540M

The Intel Core i5-540M is a mid-range dual core CPU for laptops and clocks (due to the Turbo Mode) from 2.53 to 3.06 GHz. Each core is based on the Nehalem (Westmere) micro-architecture. Hyperthreading enables the Dual Core CPU to handle 4 threads at once (for a better usage of the pipeline). Compared to the faster Core i7-620M, the 540M only has 3 MB Level 3 Cache and a lower clock speed.

A feature of the new Core i5-540M is the integrated graphics card called GMA HD and memory controller. Both are on a separate die that is still manufactured in 45nm whereas the CPU die is already manufactured in the new 32nm process.

The performance of the Core i5-540M is on average faster than a 2.8 GHz Core 2 Duo T9800 and in some benchmarks even faster than the fastest Core 2 Duo T9900 (e.g. 3DMark 06 CPU Score). Therefore, the Core i5-540M is a high end dual core cpu which should handle all daily work and gaming tasks. Only the quad core i7 CPUs can be noticeably faster at tasks that require four or more threads (e.g. rendering).

The 32nm cpu cores of the Westmere generation can also process some new instructions to accelerate AES encryptions.

The integrated Intel Graphics Media Accelerator HD (GMA HD) graphics card is known to be clocked up to 500-766 MHz and should be clearly faster than the old GMA 4500MHD. A GeForce 9400M (ION) should still be a faster (especially as Nvidia and ATI cards have a better driver support than Intel up to now). According to rumors, the GMA core will also use the Turbo Mode regulate the clock speed.

The power consumption of 35 Watt TDP (max.) counts for the whole package and therefore it is clearly better than the 35 Watt TDP of the Core 2 Duo T-series (CPU alone). Due to the Turbo Boost, the Core i5 is likely to use the whole TDP of 35 Watt under load and therefore can use more power than a similar specified Core 2 Duo. In Idle mode, the i5 uses clearly less power than the Core 2 Duo CPUs.

Intel Core i7-1355U

The Intel Core i7-1355U is a high-end mobile CPU for thin and light laptops based on the Alder Lake architecture (Raptor Lake-U / RPL-U series). It was announced in early 2023 and offers 2  performance cores (P-cores, Golden Cove architecture) and 8 efficient cores (E-cores, Gracemont architecture). The P-cores support Hyper-Threading leading to 12 supported threads when combined with the E-cores. The clock rate ranges from 1.7 to 5 GHz on the performance cluster and 1.2 to 3.7 GHz on the efficient cluster. The performance of the E-cores should be similar to old Skylake cores (compare to the Core i7-6700HQ). All cores can use up to 12 MB L3 cache. The CPU supports "Essentials" vPro management features. Compared to the P-series (28W) or H-series (45W), the 15W TDP may limit the sustained performance.

Performance

Thanks to the high clock speed, the Core i7-1355U should perform slightly better than the older core i7-1265U (up to 4.8 GHz). The faster i7 like the i7-1365U models offer only higher clock rates (and a faster iGPU).

Architecture

The integrated memory controller supports various memory types up to LPDDR5-6400. The Thread Director (in hardware) can support the operating system to decide which thread to use on the performance or efficient cores for the best performance. For AI tasks, the CPU also integrates GNA 3.0 and DL Boost (via AVX2). Quick Sync in version 8 is the same as in the Rocket Lake CPUs and supports MPEG-2, AVC, VC-1 decode, JPEG, VP8 decode, VP9, HEVC, and AV1 decode in hardware. The CPU still only supports PCIe 4.0 x8 for a GPU and two PCIe 4.0 x4 for SSDs.

The integrated graphics card is based on the Xe-architecture and offers all 96 EUs (Execution Units) operating at up to 1.3 GHz.

Power consumption

This Core i7 CPU is rated at a TDP of 15W (base power, PL1) and a maximum turbo power of 55W (PL2). The RPL-U processors are built in a further improved Intel 7 process (10nm SuperFin) that allows higher clock rates.