GeForce GT 420 vs GeForce GTX 660

Intro

Compare those specifications to the GeForce GTX 660, which makes use of a 28 nm design. nVidia has set the core frequency at 980 MHz. The GDDR5 RAM runs at a speed of 1502 MHz on this card. It features 960 SPUs as well as 80 TAUs and 24 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
GeForce GTX 660		140 Watts
	Difference: 90 Watts (180%)

Memory Bandwidth

Performance-wise, the GeForce GTX 660 should in theory be much better than the GeForce GT 420 in general. (explain)

GeForce GTX 660		144192 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 115392 (401%)

Texel Rate

The GeForce GTX 660 should be a lot (about 1300%) faster with regards to AF than the GeForce GT 420. (explain)

GeForce GTX 660		78400 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 72800 (1300%)

Pixel Rate

The GeForce GTX 660 should be much (approximately 740%) more effective at AA than the GeForce GT 420, and should be able to handle higher screen resolutions better. (explain)

GeForce GTX 660		23520 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 20720 (740%)

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 MB per second) that can be moved over the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.