GeForce GT 420 vs Radeon HD 7870 XT

Intro

Compare all that to the Radeon HD 7870 XT, which features a core clock frequency of 925 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 256-bit bus, and makes use of a 28 nm design. It is comprised of 1536 SPUs, 96 Texture Address Units, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 7870 XT		185 Watts
	Difference: 135 Watts (270%)

Memory Bandwidth

Theoretically, the Radeon HD 7870 XT should perform quite a bit faster than the GeForce GT 420 overall. (explain)

Radeon HD 7870 XT		192000 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 163200 (567%)

Texel Rate

The Radeon HD 7870 XT will be a lot (approximately 1486%) faster with regards to AF than the GeForce GT 420. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 83200 (1486%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 7870 XT is a better choice, by far. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 26800 (957%)

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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transported past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 are applied in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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