GeForce GT 640 DDR3 vs Geforce GTX 680

Intro

Compare all that to the Geforce GTX 680, which uses a 28 nm design. nVidia has set the core speed at 1006 MHz. The GDDR5 memory works at a speed of 1502 MHz on this particular card. It features 1536 SPUs along with 128 TAUs and 32 Rasterization Operator 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 680		7650 points
GeForce GT 640 DDR3		1560 points
	Difference: 6090 (390%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Geforce GTX 680		195 Watts
	Difference: 130 Watts (200%)

Memory Bandwidth

In theory, the Geforce GTX 680 should be quite a bit faster than the GeForce GT 640 DDR3 overall. (explain)

Geforce GTX 680		192256 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 135232 (237%)

Texel Rate

The Geforce GTX 680 is a lot (about 347%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Geforce GTX 680		128768 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 99968 (347%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Geforce GTX 680 is a better choice, by far. (explain)

Geforce GTX 680		32192 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 17792 (124%)

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 information (counted in megabytes per second) that can be transferred past the external memory interface within a second. The number is worked out by multiplying the bus width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics 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 that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.