GeForce GT 420 vs Radeon HD 4870 2GB

Intro

Compare that to the Radeon HD 4870 2GB, which has a GPU core clock speed of 750 MHz, and 2048 MB of GDDR5 RAM running at 900 MHz through a 256-bit bus. It also is comprised of 800(160x5) Stream Processors, 40 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 4870 2GB		150 Watts
	Difference: 100 Watts (200%)

Memory Bandwidth

The Radeon HD 4870 2GB should in theory perform much faster than the GeForce GT 420 in general. (explain)

Radeon HD 4870 2GB		115200 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 86400 (300%)

Texel Rate

The Radeon HD 4870 2GB will be much (about 436%) faster with regards to AF than the GeForce GT 420. (explain)

Radeon HD 4870 2GB		30000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 24400 (436%)

Pixel Rate

The Radeon HD 4870 2GB is quite a bit (more or less 329%) more effective at AA than the GeForce GT 420, and able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 4870 2GB		12000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 9200 (329%)

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 (counted in megabytes per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per 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 applied per second.

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