NVIDIA GeForce 840M

The NVIDIA GeForce 840M is a mid-range DirectX 12-compatible graphics card for laptops unveiled in March 2014. It is one of the first cards based on Nvidia's new Maxwell architecture (GM108 chip), but is still manufactured in 28 nm. The 840M offers 384 shader units clocked at 1029 MHz (+ Boost) as well as 2 GB of DDR3 memory (64 bit, 2000 MHz effective).

Architecture

Compared to Kepler, Maxwell has been optimized in several details to increase power efficiency. Smaller Streaming Multiprocessors (SMM) with only 128 ALUs (Kepler: 192) and an optimized scheduler should lead to better utilization of the shaders. Nvidia promises that a Maxwell SMM with 128 ALUs can offer 90 percent of the performance of a Kepler SMX with 192 ALUs. GM108 features 3 SMMs and thus 384 shader cores, 24 TMUs and 8 ROPs (64-bit interface).

Another optimization is the massively enlarged L2 cache. The larger size can process some of the memory traffic to allow for a relatively narrow memory interface without significantly reducing performance.

Similar to Fermi and Kepler, the GM107/GM108 support DirectX 12 with feature level 11_0 only.

Performance

According to our benchmarks, the GeForce 840M is about 30 percent faster than the old GT 740M and just slightly behind a GeForce GT 750M (DDR3 version). Many games of 2013/2014 can be played fluently in WXGA resolution (1366 x 768) and medium or high detail settings. However, very demanding games such as Crysis 3 or Battlefield 4 will require lower resolutions and/or details.

Features

GM108 integrates the sixth generation of the PureVideo HD video engine (VP6), offering a better decoding performance for H.264 and MPEG-2 videos. Of course, VP6 supports all features of previous generations (4K support, PIP, video encoding via NVENC API). Unfortunately, HDMI 2.0 is still not supported.

Power Consumption

The power consumption of the GeForce 840M should be about 30 Watts or lower. Therefore, the GPU is best suited for laptops 13 - 14 inches in size and above. The 800M series also supports Optimus to automatically switch between an integrated graphics card and the Nvidia GPU.

GeForce 800M Series GeForce 845M 384 @ 1.07 - 1.15 GHz 64/128 Bit @ 2000 - 5000 MHz GeForce 840M 384 @ 1.03 GHz 64 Bit @ 2000 MHz GeForce 830M 256 @ 1.03 - 1.15 GHz 64 Bit @ 1800 MHz GeForce 825M 384 @ 0.85 GHz 64 Bit @ 1800 MHz GeForce 820M 96 @ 0.78 GHz 64 Bit @ 1800 MHz
Codename	N15S-GT
Architecture	Maxwell
Pipelines	384 - unified
Core Speed	1029 MHz
Memory Speed	2000 MHz
Memory Bus Width	64 Bit
Memory Type	DDR3
Max. Amount of Memory	4 GB
Shared Memory	no
API	DirectX 12 (FL 11_0), Shader 5.0, OpenGL 4.5
Man. Technology	28 nm
Features	GPU Boost 2.0, Optimus, PhysX, CUDA, GeForce Experience, GameWorks
Notebook Size	medium sized
Date of Announcement	12.03.2014
Link to Manufacturer Page	www.nvidia.de

Benchmarks