GeForce 840M and GeForce GT 640M Mac Edition - video card comparison
GeForce 840M
GeForce GT 640M Mac Edition
Architecture
Maxwell (2014−2018)
Kepler (2012−2018)
GPU code name
N15S-GT
GK107
Market segment
Laptop
Desktop
Release date
March 2014
February 2013
Bus support
PCI Express 2.0, PCI Express 3.0
-
Interface
PCIe 3.0 x8
PCIe 3.0 x16
Boost clock speed
1124 MHz
-
Core clock speed
1029 MHz
745 MHz
Floating-point performance
863.2 gflops
572.2 gflops
Manufacturing process technology
28 nm
28 nm
Number of transistors
-
1,270 million
Pipelines / CUDA cores
384
384
Power consumption (TDP)
33 Watt
32 Watt
Texture fill rate
17.98
23.84
Memory type
DDR3
GDDR5
Maximum RAM amount
4 GB
512 MB
Memory bus width
64 Bit
64 Bit
Memory clock speed
2000 MHz
5000 MHz
Memory bandwidth
16.02 GB/s
40 GB/s
Shared memory
-
-
Display Connectors
No outputs
No outputs
DirectX
12 (11_0)
12 (11_0)
CUDA
+
3.0
OpenCL
1.2
1.2
OpenGL
4.5
4.6
Shader Model
5.1
5.1
Vulkan
1.1.126
1.1.126
GameWorks
+
-
GPU Boost
2.0
-
Optimus
+
-