Radeon HD 4870 512MB vs Radeon HD 4890 1GB

Intro

Compare all that to the Radeon HD 4890 1GB, which makes use of a 55 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM runs at a speed of 975 MHz on this specific card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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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

In theory, the Radeon HD 4890 1GB will be 8% quicker than the Radeon HD 4870 512MB overall, because of its greater data rate. (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 is quite a bit (more or less 33%) better at anisotropic 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

The Radeon HD 4890 1GB is much (about 33%) faster with regards to FSAA than the Radeon HD 4870 512MB, and will be capable of handling higher screen resolutions better. (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: Memory bandwidth is the max amount of data (counted in MB per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 amount of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at 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 that the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.