GeForce 820M and GeForce GT 640M Mac Edition - video card comparison
GeForce 820M
GeForce GT 640M Mac Edition
Architecture
Fermi (2010−2014)
Kepler (2012−2018)
GPU code name
N15V-GM
GK107
Market segment
Laptop
Desktop
Release date
January 2014
February 2013
Bus support
PCI Express 2.0
-
Interface
PCIe 2.0 x16
PCIe 3.0 x16
Core clock speed
775 MHz
745 MHz
Floating-point performance
240.0 gflops
572.2 gflops
Manufacturing process technology
28 nm
28 nm
Number of transistors
585 million
1,270 million
Pipelines / CUDA cores
96
384
Power consumption (TDP)
15 Watt
32 Watt
Texture fill rate
10.00
23.84
Memory type
DDR3
GDDR5
Maximum RAM amount
2 GB
512 MB
Memory bus width
64 Bit
64 Bit
Memory clock speed
1800 MHz
5000 MHz
Memory bandwidth
14.4 GB/s
40 GB/s
Shared memory
-
-
Display Connectors
No outputs
No outputs
DirectX
12 (11_0)
12 (11_0)
CUDA
+
3.0
OpenCL
1.1
1.2
OpenGL
4.5
4.6
Shader Model
5.1
5.1
Vulkan
N/A
1.1.126
GameWorks
+
-
GPU Boost
2.0
-
Optimus
+
-