GeForce 840M and Mobility Radeon HD 3870 - video card comparison
GeForce 840M
Mobility Radeon HD 3870
Architecture
Maxwell (2014−2018)
RV6xx (2007−2010)
GPU code name
N15S-GT
M88-XT
Market segment
Laptop
Laptop
Release date
March 2014
March 2008
Bus support
PCI Express 2.0, PCI Express 3.0
-
Interface
PCIe 3.0 x8
PCIe 2.0 x16
Boost clock speed
1124 MHz
-
Core clock speed
1029 MHz
660 MHz
Floating-point performance
863.2 gflops
422.4 gflops
Manufacturing process technology
28 nm
55 nm
Number of transistors
-
666 million
Pipelines / CUDA cores
384
320
Power consumption (TDP)
33 Watt
55 Watt
Texture fill rate
17.98
10.56
Memory type
DDR3
GDDR3
Maximum RAM amount
4 GB
512 MB
Memory bus width
64 Bit
256 Bit
Memory clock speed
2000 MHz
850 MHz
Memory bandwidth
16.02 GB/s
54.4 GB/s
Shared memory
-
-
Display Connectors
No outputs
No outputs
DirectX
12 (11_0)
10.1 (10_1)
CUDA
+
-
OpenCL
1.2
N/A
OpenGL
4.5
3.3
Shader Model
5.1
4.1
Vulkan
1.1.126
N/A
GameWorks
+
-
GPU Boost
2.0
-
Optimus
+
-