GeForce GT 640 DDR3 vs GeForce GTX 660 Ti

Intro

Compare those specifications to the GeForce GTX 660 Ti, which has a clock frequency of 915 MHz and a GDDR5 memory speed of 1500 MHz. It also uses a 192-bit bus, and makes use of a 28 nm design. It is made up of 1344 SPUs, 112 TAUs, and 24 Raster Operation Units.

Display Graphs

Hide Graphs

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 660 Ti		6013 points
GeForce GT 640 DDR3		1560 points
	Difference: 4453 (285%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 660 Ti		150 Watts
	Difference: 85 Watts (131%)

Memory Bandwidth

Theoretically, the GeForce GTX 660 Ti should perform a lot faster than the GeForce GT 640 DDR3 in general. (explain)

GeForce GTX 660 Ti		144000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 86976 (153%)

Texel Rate

The GeForce GTX 660 Ti is much (approximately 256%) better at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 660 Ti		102480 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 73680 (256%)

Pixel Rate

If running with a high screen resolution is important to you, then the GeForce GTX 660 Ti is the winner, by a large margin. (explain)

GeForce GTX 660 Ti		21960 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 7560 (53%)

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 (counted in MB per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.