GeForce GT 420 vs Geforce GTX 780

Intro

Compare all that to the Geforce GTX 780, which has a clock frequency of 863 MHz and a GDDR5 memory frequency of 1502 MHz. It also features a 384-bit memory bus, and uses a 28 nm design. It is comprised of 2304 SPUs, 192 Texture Address Units, and 48 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Geforce GTX 780		250 Watts
	Difference: 200 Watts (400%)

Memory Bandwidth

The Geforce GTX 780 should theoretically perform quite a bit faster than the GeForce GT 420 in general. (explain)

Geforce GTX 780		288384 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 259584 (901%)

Texel Rate

The Geforce GTX 780 is much (approximately 2859%) better at anisotropic filtering than the GeForce GT 420. (explain)

Geforce GTX 780		165696 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 160096 (2859%)

Pixel Rate

The Geforce GTX 780 should be a lot (about 1379%) better at full screen anti-aliasing than the GeForce GT 420, and should be able to handle higher resolutions more effectively. (explain)

Geforce GTX 780		41424 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 38624 (1379%)

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 data (measured in megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.