GeForce 840M vs GeForce GT 645M
When comparing GeForce 840M and GeForce GT 645M, we look primarily at benchmarks and game tests. But it is not only about the numbers. Often you can find third-party models with higher clock speeds, better cooling, or a customizable RGB lighting. Not all of them will have all the features you need. Another thing to consider is the port selection. Most graphics cards have at least one DisplayPort and HDMI interface, but some monitors require DVI. Before you buy, check the TDP of the graphics card - this characteristic will help you estimate the consumption of the graphics card. You may even have to upgrade your PSU to meet its requirements. An important factor when choosing between GeForce 840M and GeForce GT 645M is the price. Does the additional cost justify the performance hit? Our comparison should help you make the right decision.
GeForce 840M and GeForce GT 645M are Laptop Graphics Cards
Note: GeForce 840M and GeForce GT 645M are only used in laptop graphics. They have 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 or GeForce GT 645M here:
Main Specs
GeForce 840M
GeForce GT 645M
Power consumption (TDP)
33 Watt
32 Watt
Interface
PCIe 3.0 x8
PCIe 3.0 x16
Memory type
DDR3
DDR3\GDDR5
Maximum RAM amount
4 GB
2 GB
Display Connectors
No outputs
No outputs
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GeForce 840M has 3% more power consumption, than GeForce GT 645M.
GeForce 840M is connected by PCIe 3.0 x8, and GeForce GT 645M uses PCIe 3.0 x16 interface.
GeForce 840M has 2 GB more memory, than GeForce GT 645M.
Both cards are used in Laptops.
GeForce 840M is build with Maxwell architecture, and GeForce GT 645M - with Kepler.
GeForce 840M and GeForce GT 645M are manufactured by 28 nm process technology.
Memory clock speed of GeForce 840M is 200 MHz higher, than GeForce GT 645M.
Game benchmarks
Assassin's Creed Odyssey
Battlefield 5
Call of Duty: Warzone
Counter-Strike: Global Offensive
Cyberpunk 2077
Dota 2
Far Cry 5
Fortnite
Forza Horizon 4
Grand Theft Auto V
Metro Exodus
Minecraft
PLAYERUNKNOWN'S BATTLEGROUNDS
Red Dead Redemption 2
The Witcher 3: Wild Hunt
World of Tanks
high / 1080p
1−2
1−2
ultra / 1080p
0−1
0−1
QHD / 1440p
0−1
0−1
low / 720p
12−14
12−14
medium / 1080p
3−4
2−3
The average gaming FPS of GeForce 840M in Assassin's Creed Odyssey is 20% more, than GeForce GT 645M.
ultra / 1080p
4−5
3−4
QHD / 1440p
0−1
0−1
low / 720p
16−18
12−14
medium / 1080p
5−6
4−5
The average gaming FPS of GeForce 840M in Battlefield 5 is 28% more, than GeForce GT 645M.
low / 768p
45−50
50−55
high / 1080p
40−45
45−50
QHD / 1440p
0−1
0−1
The average gaming FPS of GeForce GT 645M in Call of Duty: Warzone is 11% more, than GeForce 840M.
low / 768p
120−130
110−120
medium / 768p
90−95
85−90
ultra / 1080p
40−45
35−40
QHD / 1440p
24−27
−
4K / 2160p
18−20
10−11
high / 768p
65−70
60−65
The average gaming FPS of GeForce 840M in Counter-Strike: Global Offensive is 11% more, than GeForce GT 645M.
low / 768p
85−90
70−75
ultra / 1080p
16−18
14−16
medium / 1080p
40−45
45−50
The average gaming FPS of GeForce 840M in Cyberpunk 2077 is 8% more, than GeForce GT 645M.
low / 768p
75−80
70−75
medium / 768p
50−55
45−50
ultra / 1080p
24−27
18−20
The average gaming FPS of GeForce 840M in Dota 2 is 10% more, than GeForce GT 645M.
high / 1080p
2−3
2−3
ultra / 1080p
2−3
2−3
4K / 2160p
0−1
0−1
low / 720p
12−14
10−11
medium / 1080p
3−4
3−4
The average gaming FPS of GeForce 840M in Far Cry 5 is 25% more, than GeForce GT 645M.
high / 1080p
10−11
−
ultra / 1080p
5−6
5−6
QHD / 1440p
2−3
1−2
low / 720p
50−55
45−50
medium / 1080p
10−12
8−9
The average gaming FPS of GeForce 840M in Fortnite is 13% more, than GeForce GT 645M.
high / 1080p
4−5
3−4
QHD / 1440p
0−1
0−1
low / 720p
16−18
14−16
medium / 1080p
7−8
6−7
The average gaming FPS of GeForce 840M in Forza Horizon 4 is 12% more, than GeForce GT 645M.
low / 768p
45−50
40−45
high / 1080p
5−6
3−4
ultra / 1080p
2−3
2−3
QHD / 1440p
0−1
0−1
medium / 720p
35−40
35−40
The average gaming FPS of GeForce 840M in Grand Theft Auto V is 9% more, than GeForce GT 645M.
high / 1080p
1−2
1−2
ultra / 1080p
0−1
0−1
4K / 2160p
0−1
0−1
low / 720p
5−6
3−4
medium / 1080p
3−4
2−3
The average gaming FPS of GeForce 840M in Metro Exodus is 50% more, than GeForce GT 645M.
low / 768p
90−95
85−90
high / 1080p
85−90
55−60
ultra / 1080p
70−75
−
medium / 1080p
90−95
−
The average gaming FPS of GeForce 840M in Minecraft is 25% more, than GeForce GT 645M.
high / 1080p
−
14−16
ultra / 1080p
12−14
12−14
low / 720p
27−30
24−27
medium / 1080p
14−16
14−16
The average gaming FPS of GeForce 840M in PLAYERUNKNOWN'S BATTLEGROUNDS is 5% more, than GeForce GT 645M.
ultra / 1080p
4−5
3−4
QHD / 1440p
0−1
0−1
low / 720p
6−7
4−5
The average gaming FPS of GeForce 840M in Red Dead Redemption 2 is 25% more, than GeForce GT 645M.
low / 768p
12−14
8−9
medium / 768p
9−10
7−8
high / 1080p
4−5
3−4
ultra / 1080p
3−4
3−4
4K / 2160p
0−1
0−1
The average gaming FPS of GeForce 840M in The Witcher 3: Wild Hunt is 40% more, than GeForce GT 645M.
low / 768p
75−80
70−75
medium / 768p
35−40
35−40
ultra / 1080p
16−18
12−14
high / 768p
30−35
30−33
The average gaming FPS of GeForce 840M in World of Tanks is 7% more, than GeForce GT 645M.
Full Specs
GeForce 840M
GeForce GT 645M
Architecture
Maxwell
Kepler
Code name
N15S-GT
N13P-GS
Type
Laptop
Laptop
Release date
12 March 2014
22 March 2012
Pipelines
384
384
Core clock speed
1029 MHz
Boost Clock
1124 MHz
Transistor count
1,270 million
Manufacturing process technology
28 nm
28 nm
Texture fill rate
17.98
22.7 billion/sec
Floating-point performance
863.2 gflops
544.5 gflops
Memory bus width
64 Bit
128bit
Memory clock speed
2000 MHz
1800 MHz
Memory bandwidth
16.02 GB/s
Shared memory
-
-
DirectX
12 (11_0)
12 API
Shader Model
5.1
5.1
OpenGL
4.5
4.5
OpenCL
1.2
1.1
Vulkan
1.1.126
1.1.126
CUDA
+
+
CUDA cores
384
Bus support
PCI Express 2.0, PCI Express 3.0
PCI Express 2.0, PCI Express 3.0
HDMI
+
HDCP
+
Maximum VGA resolution
Up to 2048x1536
3D Blu-Ray
+
Bitcoin / BTC (SHA256)
92 Mh/s
19 Mh/s
Laptop size
medium sized
medium sized
Optimus
+
+
GPU Boost
2.0
GameWorks
+
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