Intel Iris Plus Graphics 640 vs Intel UHD Graphics 605

Intel Iris Plus Graphics 640

The Intel Iris Plus Graphics 640 (GT3e) is a processor graphics card for Kaby Lake models announced in January 2017. As the successor to the Intel Iris Graphics 540 (Skylake), the Iris Plus Graphics 640 is used for 15-Watt ULV models and is equipped with 64 MB eDRAM cache. There should not be any big changes compared to the Iris Graphics 540.

The so called GT3e version of the Kaby Lake GPU still has 48 Execution Units (EUs), which can reach up to 1050 MHz depending on the model. Besides eDRAM cache, the Iris 640 can also access the system memory (2x 64 Bit DDR3L-1600/LPDDR3-1866/DDR4-2400) via processor interface.

Compared to the Iris Plus 650 from the 28-Watt models, the Iris 640 only has a slightly lower maximum clock as well as the lower TDP, so the utilization of the Turbo Boost potential should be worse.

Performance

The exact performance of the Iris Plus Graphics 640 depends on the CPU model, because maximum clock as well as the size of the L3 cache can differ a bit. The system memory (DDR3/DDR4) will influence the performance as well.

The fastest chips are high-clocked Core i7 models like the Core i7-7660U. Depending on the game, the Iris Plus 640 will probably be similar to the previous model somewhere between a dedicated GeForce 920M and GeForce 940M and is usually limited to low settings in modern games.

Features

The reworked video engine now fully supports hardware decoding of H.265/HEVC videos. Contrary to Skylake, however, Kaby Lake can now also decode H.265/HEVC Main 10 with a 10-bit color depth as well as Google's VP9 codec. The video output is possible via DP 1.2/eDP 1.3 (up to 3840 x 2160 @60 Hz), whereas HDMI is also supported in the older 1.4a standard. An HDMI 2.0 output can be added via converter from DisplayPort. The GPU can drive up to three displays simultaneously.

Power Consumption

The Iris Plus Graphics 640 is used for 15-Watt ULV processor and therefore thin notebooks and Ultrabooks.

Intel UHD Graphics 605

The Intel UHD Graphics 605 is an integrated processor graphics unit from the Gemini Lake generation (e. g. Pentium Silver N5000), which was announced late 2017. The GPU can convince with low consumption figures, but the performance is only in the low-end segment and is rarely sufficient for modern games. Being the maximum configuration of the Gemini Lake GPU, the UHD Graphics 605 is equipped with 18 Execution Units (EUs) running at up to 750 MHz. The technical specifications of the GPU are based on Intel's Gen9 architecture, which is also used for the more expensive Skylake series and also in the predecessor HD Graphics 505.

Due to its lack of dedicated graphics memory or eDRAM cache, the UHD 605 has to access the main memory via processor (2x 64bit DDR4/LPDDR4-2400).

Performance

The UHD Graphics 605 offers a similar performance as the Intel HD Graphics 505 in the Apollo Lake SoCs (same Gen 9 architecture). Therefore, the GPU is only suited for some very low demanding games like Dirt Rally or Sims 4.

Features

The video engine decodes H.265/HEVC (8b and 10b) and VP9 completely in hardware. Up to three displays can be connected via DP 1.2a/eDP 1.3 or HDMI 2.0a (including HDCP 2.2).

Power Consumption

The TDP of the whole Pentium Silver N5000 chip is 6 Watts by default, so the GPU is primarily used for (often passively cooled) netbooks or thin notebooks. The TDP can also be reduced to 4.9 Watts, but this will obviously affect the performance.