GeForce 840M vs GeForce GTX 660

In this comparison between GeForce 840M and GeForce GTX 660 you will find out which graphics card performs better in today's games. Bear in mind that third-party versions may have more efficient cooling and higher clock speeds. This will increase cards' performance, though not by much. In addition to raw power you should also take into account the dimensions. Thicker models simply will not fit into a small mini-ITX case. The resolution of your monitor also affects the choice, since 4K gameplay requires a more powerful GPU. And don't overspend on the graphics card. Other parts of your build may also need to be upgraded, save some money for the CPU or power supply. For some people GeForce 840M will be the best choice, for others GeForce GTX 660 will be their preference. Study the comparison tables below and make your choice.

GeForce 840M is a Laptop Graphics Card

Note: GeForce 840M is only used in laptop graphics. It has lower GPU clock speed compared to the desktop variant, which results in lower power consumption, but also 10-30% lower gaming performance. Check available laptop models with GeForce 840M here:

Main Specs

  GeForce 840M GeForce GTX 660
Power consumption (TDP) 33 Watt 140 Watt
Interface PCIe 3.0 x8 PCIe 3.0 x16
Supplementary power connectors One 6-pin
Memory type DDR3 GDDR5
Maximum RAM amount 4 GB 2 GB
Display Connectors No outputs 2x DVI, 1x HDMI, 1x DisplayPort
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  • GeForce GTX 660 has 324% more power consumption, than GeForce 840M.
  • GeForce 840M is connected by PCIe 3.0 x8, and GeForce GTX 660 uses PCIe 3.0 x16 interface.
  • GeForce 840M has 2 GB more memory, than GeForce GTX 660.
  • GeForce 840M is used in Laptops, and GeForce GTX 660 - in Desktops.
  • GeForce 840M is build with Maxwell architecture, and GeForce GTX 660 - with Kepler.
  • Core clock speed of GeForce 840M is 49 MHz higher, than GeForce GTX 660.
  • GeForce 840M and GeForce GTX 660 are manufactured by 28 nm process technology.
  • Memory clock speed of GeForce 840M is 1994 MHz higher, than GeForce GTX 660.

Game benchmarks

high / 1080p 1−2 20−22
ultra / 1080p 0−1 12−14
QHD / 1440p 0−1 6−7
4K / 2160p 5−6
low / 720p 12−14 40−45
medium / 1080p 3−4 24−27
The average gaming FPS of GeForce GTX 660 in Assassin's Creed Odyssey is 383% more, than GeForce 840M.

Full Specs

  GeForce 840M GeForce GTX 660
Architecture Maxwell Kepler
Code name N15S-GT GK106
Type Laptop Desktop
Release date 12 March 2014 6 September 2012
Pipelines 384 960
Core clock speed 1029 MHz 980 MHz
Boost Clock 1124 MHz 1033 MHz
Transistor count 2,540 million
Manufacturing process technology 28 nm 28 nm
Texture fill rate 17.98 78.4 billion/sec
Floating-point performance 863.2 gflops 1,981 gflops
Length 9.5" (24.1 cm)
Memory bus width 64 Bit 192-bit GDDR5
Memory clock speed 2000 MHz 6.0 GB/s
Memory bandwidth 16.02 GB/s 144.2 GB/s
Shared memory -
DirectX 12 (11_0) 12 (11_0)
Shader Model 5.1 5.1
OpenGL 4.5 4.3
OpenCL 1.2 1.2
Vulkan 1.1.126 1.1.126
CUDA + +
CUDA cores 960
Bus support PCI Express 2.0, PCI Express 3.0 PCI Express 3.0
Height 4.376" (11.1 cm)
SLI options +
Multi monitor support 4 displays
HDMI +
HDCP +
Maximum VGA resolution 2048x1536
Audio input for HDMI Internal
3D Blu-Ray +
3D Gaming +
3D Vision +
Bitcoin / BTC (SHA256) 92 Mh/s 66 Mh/s
Laptop size medium sized
Optimus +
GPU Boost 2.0
GameWorks +
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