Intel Iris Plus Graphics 640 vs Intel UHD Graphics 617 vs Intel Iris Plus Graphics 655

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 617

The Intel UHD Graphics 617 (GT2) is a low-end integrated graphics unit, which can be found in the Y-series of the Amber-Lake generation. This "GT2" version offers 24 Execution Units (EUs) clocked at up to 1050 MHz (depending on the CPU model). Due to its lack of dedicated graphics memory or eDRAM cache, the UHD 617 has to access the main memory (2x 64bit DDR3L/LPDDR3). Compared to the old HD Graphics 615 in Kaby-Lake-Y CPUs, the UHD 617 is the same GPU with slightly different clock speeds (depending on the model) and slight power/performance improvements due to the improved 14nm++ process. Compared to the similar UHD Graphics 615 in other Amber Lake models, the 617 looks to be higher clocked (+50 MHz) and has more headroom due to the higher TDP of 7 versus 5 Watt.

Performance

The 3D performance of the UHD 617 depends on the CPU model and the cooling / TDP-setting of the laptop. Furthermore, the used main memory (single channel, DDR3(L), amount) is influencing performance. On average the UHD graphics 617 should be very similar to the Kaby-Lake HD Graphics 615 due to the same architecture and similar speeds. That means that only low demanding games like Farming Simulator 17 or Rocket League are playable in lowest detail settings.

Features

The revised video engine in the HD 615 and UHD 615 / 617 now supports H.265/HEVC Main10 profile in hardware with 10 bit colors. Furthermore, Googles VP9 codec can also be hardware decoded. The UHD 617 should support HDCP 2.2 and therefore Netflix 4K. HDMI 2.0 however is still only supported with an external converter chip (LSPCon).

Power Consumption

The UHD Graphics 617 can be found in Y processors with 7 W TDP  and is therefore suited for very thin, mostly passively cooled subnotebooks like the MacBook Air 2018.

Intel Iris Plus Graphics 655