GeForce GT 420 vs Radeon HD 3690/3830

Intro

Compare all of that to the Radeon HD 3690/3830, which comes with a clock frequency of 668 MHz and a GDDR3 memory frequency of 828 MHz. It also makes use of a 128-bit bus, and makes use of a 55 nm design. It features 320(64x5) SPUs, 16 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 3690/3830		75 Watts
	Difference: 25 Watts (50%)

Memory Bandwidth

The GeForce GT 420 should in theory perform a small bit faster than the Radeon HD 3690/3830 in general. (explain)

GeForce GT 420		28800 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 2304 (9%)

Texel Rate

The Radeon HD 3690/3830 will be a lot (approximately 91%) more effective at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 3690/3830		10688 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 5088 (91%)

Pixel Rate

The Radeon HD 3690/3830 should be much (more or less 282%) faster with regards to full screen anti-aliasing than the GeForce GT 420, and also should be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 3690/3830		10688 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 7888 (282%)

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 information (counted in megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 amount of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the 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 card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.