GeForce GT 640 DDR3 vs Geforce GTX 770

Intro

Compare all of that to the Geforce GTX 770, which makes use of a 28 nm design. nVidia has set the core speed at 1046 MHz. The GDDR5 RAM runs at a frequency of 1753 MHz on this particular card. It features 1536 SPUs as well as 128 TAUs and 32 ROPs.

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 770		7854 points
GeForce GT 640 DDR3		1560 points
	Difference: 6294 (403%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Geforce GTX 770		230 Watts
	Difference: 165 Watts (254%)

Memory Bandwidth

As far as performance goes, the Geforce GTX 770 should theoretically be a lot superior to the GeForce GT 640 DDR3 overall. (explain)

Geforce GTX 770		224384 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 167360 (293%)

Texel Rate

The Geforce GTX 770 will be much (approximately 365%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Geforce GTX 770		133888 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 105088 (365%)

Pixel Rate

The Geforce GTX 770 will be a lot (approximately 132%) more effective at AA than the GeForce GT 640 DDR3, and will be capable of handling higher resolutions while still performing well. (explain)

Geforce GTX 770		33472 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 19072 (132%)

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: Bandwidth is the largest amount of information (in units of megabytes per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the interface width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.