Radeon HD 4870 512MB vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which has core speeds of 1000 MHz on the GPU, and 975 MHz on the 1024 MB of GDDR5 RAM. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 40 Watts (27%)

Memory Bandwidth

Performance-wise, the Radeon HD 4890 1GB should in theory be a small bit superior to the Radeon HD 4870 512MB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 9600 (8%)

Texel Rate

The Radeon HD 4890 1GB should be quite a bit (about 33%) better at texture filtering than the Radeon HD 4870 512MB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 10000 (33%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4890 1GB is the winner, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 4870 512MB		12000 Mpixels/sec
	Difference: 4000 (33%)

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 data (counted in megabytes per second) that can be transported across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.