NVIDIA GeForce 940MX vs AMD Radeon RX 580 (Desktop) vs NVIDIA GeForce 920M

NVIDIA GeForce 940MX

The Nvidia GeForce 940MX is a mid-range laptop graphics card with DirectX 12 support (FL 11_0). It has been announced in the first quarter of 2016 and is the refresh of the GeForce 940M. Compared to the older card, the new one is based on the same chip but now supports faster GDDR5. Therefore, it is similar to the Maxwell GPU in the Microsoft Surface Book but with more memory and higher clock speeds. However, most notebook vendors will use the slower DDR3 version of the 940MX that clocks only a few percent faster than the old GeForce 940M (1122 versus 1072 MHz base clock e.g.). 

For the GDDR5 version of the 940MX there appears to be also a variant with the GM107-B chip with 512 shaders instead of the 384 but lower clock speeds. The 940MX in the Acer Aspire E5-774G e.g. featured 512 shader cores (GM107) clocked at 795 - 861 MHz. The Dell Inspiron 17 7778 version however had the GM108 chip with 384 shaders clocked at 1083 - 1189 MHz.

The performance greatly depends on the used graphics memory and chip. According to our benchmarks (see below), the DDR3 version is very similar to the old 940M (due to only minor increased clock rates). The GDDR5 version however pushes ahead 20% (even 30% if paired with a fast desktop quad-core, but we lack 940M reference scores). Therefore, demanding games from 2015 should run fluently in low to medium settings and WXGA resolution. 

The TDP of the card should be rated at about 15 to 30 Watt (depending on the version, clock speeds and memory). Therefore, the GPU is best suited for laptops from 13-inch and up.

AMD Radeon RX 580 (Desktop)

NVIDIA GeForce 920M

The NVIDIA GeForce 920M (sometimes also NVIDIA GeForce GT 920M) is an entry level DirectX 12 graphics card. It is based on the 28 nm Kepler architecture and uses the same GK208 chip as the GeForce GT 730M, 825M and 740M. The 384 shaders are clocked at 954 MHz, while the memory (64-bit DDR3 interface) runs at 900 MHz (1800 MHz effective).

Architecture

GK208 is based on the Kepler architecture and offers two shader blocks, called SMX, each with 192 shaders for a total of 384 shader cores. The shaders are clocked at the same speed as the rest of the chip. Furthermore, the GK208 chip has 16 TMUs and 8 ROPs on a 64-bit memory interface.

PCIe 3.0 is now supported by the mobile Kepler series and GPU Boost 2.0 mode can automatically overclock the card if the laptop cooling system allows it. This feature is available on any notebook with a graphics card from the 800M series.

Performance

The GeForce 920M offers a performance similar to the AMD Radeon R7 M260 or R7 M360 and will handle modern games (as of 2014/2015) in low settings only. For comparison, a GeForce 930M is about 20 to 30 percent faster than the 920M.

Features

The feature set of the 920M corresponds to the GT 730M and 825M. This includes support for up to 4 active displays. Furthermore, high resolution monitors of up to 3840x2160 pixels can now be connected using DisplayPort 1.2 or HDMI 1.4a if available. HD-Audio codecs, such as Dolby TrueHD and DTS-HD, can be transmitted via bitstream mode through the HDMI port. However, as most laptops will feature Optimus, the integrated GPU will likely have direct control over the display ports and may limit the feature set available by the Nvidia Kepler cards.

The 5th generation PureVideo HD video processor (VP5) offers hardware decoding of HD videos. Common codecs such as MPEG-1/2, MPEG-4 ASP, H.264 and VC1/WMV9 are fully supported up to 4K resolutions while VC1 and MPEG-4 are supported up to 1080p. Two streams can be decoded in parallel for features such as Picture-in-Picture. Another feature is the inclusion of a dedicated video encoding engine similar to Intel QuickSync that can be accessed via the NVENCI API.

Power Consumption

The power consumption of the GeForce 920M is similar to the 825M and suited for 13-inch laptops and above.