GeForce 9800 GTX vs GeForce GT 420

Intro

Compare that to the GeForce GT 420, which comes with a clock frequency of 700 MHz and a GDDR3 memory speed of 900 MHz. It also uses a 128-bit bus, and makes use of a 40 nm design. It is made up of 48 SPUs, 8 Texture Address Units, and 4 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
GeForce 9800 GTX		140 Watts
	Difference: 90 Watts (180%)

Memory Bandwidth

The GeForce 9800 GTX should theoretically perform much faster than the GeForce GT 420 overall. (explain)

GeForce 9800 GTX		70400 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 41600 (144%)

Texel Rate

The GeForce 9800 GTX is a lot (about 671%) more effective at AF than the GeForce GT 420. (explain)

GeForce 9800 GTX		43200 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 37600 (671%)

Pixel Rate

If using a high screen resolution is important to you, then the GeForce 9800 GTX is the winner, and very much so. (explain)

GeForce 9800 GTX		10800 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 8000 (286%)

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 past the external memory interface within a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.