GeForce GT 640 DDR3 vs GeForce GTX 650 Ti 2GB

Intro

Compare those specifications to the GeForce GTX 650 Ti 2GB, which makes use of a 28 nm design. nVidia has clocked the core frequency at 928 MHz. The GDDR5 RAM is set to run at a frequency of 1350 MHz on this specific card. It features 768 SPUs along with 64 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 650 Ti 2GB		110 Watts
	Difference: 45 Watts (69%)

Memory Bandwidth

As far as performance goes, the GeForce GTX 650 Ti 2GB should in theory be quite a bit superior to the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 650 Ti 2GB		86400 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 29376 (52%)

Texel Rate

The GeForce GTX 650 Ti 2GB will be a lot (more or less 106%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 650 Ti 2GB		59392 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 30592 (106%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GTX 650 Ti 2GB is the winner, but not by far. (explain)

GeForce GTX 650 Ti 2GB		14848 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 448 (3%)

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 maximum amount of data (measured in MB per second) that can be moved across the external memory interface in a second. It's calculated by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.