Radeon HD 4830 512MB vs Radeon HD 4870 1GB

Intro

Compare those specs to the Radeon HD 4870 1GB, which comes with a clock speed of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also uses a 256-bit bus, and makes use of a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 55 Watts (58%)

Memory Bandwidth

As far as performance goes, the Radeon HD 4870 1GB should in theory be quite a bit superior to the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 57600 (100%)

Texel Rate

The Radeon HD 4870 1GB should be a lot (more or less 63%) faster with regards to texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4870 1GB		30000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 11600 (63%)

Pixel Rate

The Radeon HD 4870 1GB should be quite a bit (about 30%) more effective at FSAA than the Radeon HD 4830 512MB, and also capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 4870 1GB		12000 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 2800 (30%)

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 largest amount of information (measured in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the 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 processed per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.