GeForce GT 640 vs GeForce GT 645M

If you are going to buy a new graphics card and are choosing between GeForce GT 640 and GeForce GT 645M, there are a couple of things to consider. Cards with more VRAM in general perform better and allow you to play on higher graphics settings. Size also makes a difference. A model with a large heatsink can occupy up to three expansion slots on a motherboard. Be sure you have enough room in your PC case. When comparing GPUs with different architectures, more processing cores and even higher TFLOPS will not always translate to better performance. To help you decide which GPU you need, we have measured frame rates in a number of popular games. For more on how the GeForce GT 640 stacks up against GeForce GT 645M, check out specs charts below.

GeForce GT 645M is a Laptop Graphics Card

Note: GeForce GT 645M 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 GT 645M here:

Main Specs

  GeForce GT 640 GeForce GT 645M
Power consumption (TDP) 65 Watt 32 Watt
Interface PCIe 3.0 x16 PCIe 3.0 x16
Supplementary power connectors None
Memory type DDR3 DDR3\GDDR5
Maximum RAM amount 2 GB 2 GB
Display Connectors 1x DVI, 1x HDMI, 1x DisplayPort No outputs
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  • GeForce GT 640 has 103% more power consumption, than GeForce GT 645M.
  • Both video cards are using PCIe 3.0 x16 interface connection to a motherboard.
  • GeForce GT 640 and GeForce GT 645M have maximum RAM of 2 GB.
  • GeForce GT 640 is used in Desktops, and GeForce GT 645M - in Laptops.
  • GeForce GT 640 and GeForce GT 645M are build with Kepler architecture.
  • GeForce GT 640 and GeForce GT 645M are manufactured by 28 nm process technology.
  • Memory clock speed of GeForce GT 645M is 18 MHz higher, than GeForce GT 640.

Game benchmarks

high / 1080p 2−3 1−2
ultra / 1080p 1−2 0−1
QHD / 1440p 0−1 0−1
low / 720p 14−16 12−14
medium / 1080p 5−6 2−3
The average gaming FPS of GeForce GT 640 in Assassin's Creed Odyssey is 40% more, than GeForce GT 645M.

Full Specs

  GeForce GT 640 GeForce GT 645M
Architecture Kepler Kepler
Code name GK107 N13P-GS
Type Desktop Laptop
Release date 5 June 2012 22 March 2012
Pipelines 384 384
Core clock speed 902 MHz
Transistor count 1,270 million 1,270 million
Manufacturing process technology 28 nm 28 nm
Texture fill rate 28.86 22.7 billion/sec
Floating-point performance 692.7 gflops 544.5 gflops
Length 145 mm
Memory bus width 128 Bit 128bit
Memory clock speed 1782 MHz 1800 MHz
Memory bandwidth 28.51 GB/s
Shared memory -
DirectX 12 (11_0) 12 API
Shader Model 5.1 5.1
OpenGL 4.6 4.5
OpenCL 1.2 1.1
Vulkan 1.1.126 1.1.126
CUDA 3.0 +
CUDA cores 384
Bus support PCI Express 2.0, PCI Express 3.0
HDMI +
HDCP +
Maximum VGA resolution Up to 2048x1536
3D Blu-Ray +
Bitcoin / BTC (SHA256) 24 Mh/s 19 Mh/s
Laptop size medium sized
Optimus +
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