AMD Radeon RX Vega 56 vs Intel Iris Plus Graphics 655

AMD’s Radeon RX Vega 56 is a high-end desktop GPU that was first introduced in August of 2017. It is based on the Vega architecture (Vega 10) and equipped with fast HBM2 VRAM. When it was first introduced, it was the second fastest AMD GPU available, only bested by the RX Vega 64 that launched on the very same day. At the time of writing, both GPUs have been replaced by their respective Radeon VII successors.

The RX Vega 56 reference design features 56 CUs running at 1,138-1,474 MHz (Boost) and 8 GB of HBM2 VRAM running at 800 MHz connected via a 2,048-bit memory bus resulting in a memory bandwidth of 409.6 GB/s.

Features

Vega 10 is still produced in a 10-nm manufacturing process. The die consists of roughly 12.5 billion transistors and measures 495 mm2 in size. The newer Vega 20 chip, which AMD’s current Radeon VII is based on, features around 13.2 billion transistors. Applications have access to a total of 3,584 shaders, but the GPU lacks the dedicated Raytracing and Tensor cores that can be found on Nvidia’s latest RTX generation of GPUs.

Performance

Performance-wise, the RX Vega 56 is comparable to an Nvidia GeForce GTX 1070, and thus best categorized as upper middle-class. Games released in 2018 and 2019 should run perfectly fine and smooth in high details on WQHD (2560 x 1440).

Power Consumption

According to AMD, the RX Vega 56’s maximum power consumption is 210 W. Given the GTX 1070’s power consumption of just 150 W, the Vega 56 cannot keep up with its direct competitor in regards to performance-per-watt ratio.

The Intel Iris Plus Graphics 655 (GT3e) is a processor graphics card announced in September 2017. As the successor to the Intel Iris Graphics 650 (Kaby Lake), the Iris Plus Graphics 655 is used for 28-Watt Coffee Lake-U models. The biggest difference is the doubled eDRAM-cache at 128 MB. There should not be any big changes compared to the Iris Graphics 650.

The so called GT3e version of the Kaby Lake GPU still has 48 Execution Units (EUs), which can reach up to 1200 MHz (previously 1100 MHz) depending on the model. Besides eDRAM cache, the Iris 655 can also access the system memory (2x 64 Bit DDR3L-2133/DDR4-2400) via processor interface.

Compared to the Iris Plus 640 from the 15-Watt models, the Iris 655 only has a slightly higher maximum clock as well as almost twice the TDP, which allows a better utilization of the Turbo Boost potential.

Performance

The exact performance of the Iris Plus Graphics 655 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 i7-8559U. Depending on the game, the Iris Plus 655 will probably be on par with a dedicated GeForce 930M or GeForce 940MX and can handle smooth gameplay in modern titles in low up to medium settings.

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 655 is used for 28-Watt processor and therefore small/medium-sized notebooks.