Radeon HD 3870 1GB vs Radeon HD 4830 1GB

Intro

Compare those specs to the Radeon HD 4830 1GB, which features a core clock speed of 575 MHz and a GDDR4 memory speed of 900 MHz. It also uses a 256-bit memory bus, and makes use of a 55 nm design. It features 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 3870 1GB		106 Watts
	Difference: 11 Watts (12%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 1GB should be 25% faster than the Radeon HD 4830 1GB in general, because of its greater bandwidth. (explain)

Radeon HD 3870 1GB		72000 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 14400 (25%)

Texel Rate

The Radeon HD 4830 1GB should be quite a bit (approximately 48%) more effective at texture filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 4830 1GB		18400 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 6000 (48%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 3870 1GB is superior to the Radeon HD 4830 1GB, by far. (explain)

Radeon HD 3870 1GB		12400 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 3200 (35%)

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 max amount of information (counted in megabytes per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. 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 are processed in one second. This figure is worked out by multiplying the total amount of texture units of the card 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 could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.