GeForce GT 640 DDR3 vs Geforce GTX 670

Intro

Compare all of that to the Geforce GTX 670, which comes with a GPU core clock speed of 915 MHz, and 2048 MB of GDDR5 memory set to run at 1500 MHz through a 256-bit bus. It also features 1344 Stream Processors, 112 Texture Address Units, and 32 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 670		7351 points
GeForce GT 640 DDR3		1560 points
	Difference: 5791 (371%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Geforce GTX 670		170 Watts
	Difference: 105 Watts (162%)

Memory Bandwidth

The Geforce GTX 670 should in theory be much faster than the GeForce GT 640 DDR3 overall. (explain)

Geforce GTX 670		192000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 134976 (237%)

Texel Rate

The Geforce GTX 670 is much (more or less 256%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Geforce GTX 670		102480 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 73680 (256%)

Pixel Rate

The Geforce GTX 670 will be quite a bit (approximately 103%) better at full screen anti-aliasing than the GeForce GT 640 DDR3, and should be capable of handling higher screen resolutions more effectively. (explain)

Geforce GTX 670		29280 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 14880 (103%)

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 max amount of data (in units of megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.