GeForce GT 640 DDR3 vs GeForce GTX 970M

Intro

Compare those specs to the GeForce GTX 970M, which comes with a core clock frequency of 924 MHz and a GDDR5 memory speed of 1000 MHz. It also uses a 192-bit memory bus, and uses a 28 nm design. It is made up of 1280 SPUs, 80 TAUs, and 48 Raster Operation Units.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

GeForce GTX 970M		7520 points
GeForce GT 640 DDR3		1560 points
	Difference: 5960 (382%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 970M		75 Watts
	Difference: 10 Watts (15%)

Memory Bandwidth

Performance-wise, the GeForce GTX 970M should theoretically be quite a bit superior to the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 970M		96000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 38976 (68%)

Texel Rate

The GeForce GTX 970M should be quite a bit (about 157%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

GeForce GTX 970M		73920 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 45120 (157%)

Pixel Rate

The GeForce GTX 970M should be quite a bit (more or less 208%) better at full screen anti-aliasing than the GeForce GT 640 DDR3, and also will be able to handle higher screen resolutions more effectively. (explain)

GeForce GTX 970M		44352 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 29952 (208%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (counted in MB per second) that can be moved past the external memory interface within a second. It's calculated by multiplying the interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.