Radeon HD 4830 512MB vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which features core speeds of 1000 MHz on the GPU, and 975 MHz on the 1024 MB of GDDR5 memory. It features 800(160x5) SPUs as well as 40 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 95 Watts (100%)

Memory Bandwidth

In theory, the Radeon HD 4890 1GB should perform quite a bit faster than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4890 1GB		124800 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 67200 (117%)

Texel Rate

The Radeon HD 4890 1GB is a lot (approximately 117%) more effective at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 21600 (117%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 4890 1GB is superior to the Radeon HD 4830 512MB, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
Radeon HD 4830 512MB		9200 Mpixels/sec
	Difference: 6800 (74%)

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 (counted in megabytes per second) that can be moved across the external memory interface in a second. It's worked out by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number 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 worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.