Radeon HD 4830 512MB vs Radeon HD 7790

Intro

Compare those specifications to the Radeon HD 7790, which comes with core speeds of 1000 MHz on the GPU, and 1500 MHz on the 1024 MB of GDDR5 memory. It features 896 SPUs as well as 56 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7790		85 Watts
Radeon HD 4830 512MB		95 Watts
	Difference: 10 Watts (12%)

Memory Bandwidth

In theory, the Radeon HD 7790 should be 67% faster than the Radeon HD 4830 512MB in general, because of its higher data rate. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 38400 (67%)

Texel Rate

The Radeon HD 7790 will be a lot (approximately 204%) more effective at texture filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 37600 (204%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 7790 is a better choice, by a large margin. (explain)

Radeon HD 7790		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: Memory bandwidth is the largest amount of information (counted in megabytes per second) that can be moved past the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the 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 number of texture map elements (texels) that are applied in one second. This is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.