GeForce GT 420 vs GeForce GTX 660

Intro

Compare that to the GeForce GTX 660, which comes with core clock speeds of 980 MHz on the GPU, and 1502 MHz on the 2048 MB of GDDR5 memory. It features 960 SPUs along with 80 TAUs and 24 ROPs.

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

Theoretically speaking, the GeForce GTX 660 should be 401% faster than the GeForce GT 420 overall, because of its greater bandwidth. (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%) more effective at texture filtering 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 quite a bit (approximately 740%) faster with regards to AA than the GeForce GT 420, and also capable of handling higher screen resolutions without slowing down too much. (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: Bandwidth is the maximum amount of information (measured in MB per second) that can be moved past the external memory interface within a second. It's worked out by multiplying the bus width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.