GeForce GT 420 vs Radeon HD 4870 X2

Intro

Compare that to the Radeon HD 4870 X2, which comes with a clock frequency of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also features a 256-bit bus, and uses a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, 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 X2		350 Watts
	Difference: 300 Watts (600%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 X2 should theoretically be a lot superior to the GeForce GT 420 overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 201600 (700%)

Texel Rate

The Radeon HD 4870 X2 should be much (approximately 971%) better at anisotropic filtering than the GeForce GT 420. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 54400 (971%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4870 X2 is superior to the GeForce GT 420, by far. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 21200 (757%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (in units of megabytes per second) that can be transported past the external memory interface in one second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen 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 this number, the better the video 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 most pixels the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the core 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 many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.