GeForce GT 420 vs Radeon HD 4870 1GB

Intro

Compare those specifications to the Radeon HD 4870 1GB, which makes use of a 55 nm design. AMD has set the core frequency at 750 MHz. The GDDR5 RAM is set to run at a speed of 900 MHz on this card. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 100 Watts (200%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 1GB should theoretically be much better than the GeForce GT 420 in general. (explain)

Radeon HD 4870 1GB		115200 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 86400 (300%)

Texel Rate

The Radeon HD 4870 1GB should be a lot (about 436%) better at texture filtering than the GeForce GT 420. (explain)

Radeon HD 4870 1GB		30000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 24400 (436%)

Pixel Rate

The Radeon HD 4870 1GB should be much (about 329%) better at AA than the GeForce GT 420, and also able to handle higher screen resolutions better. (explain)

Radeon HD 4870 1GB		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 largest amount of data (measured in megabytes per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is worked out by multiplying the total amount 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.