Radeon HD 4650 512MB vs Radeon HD 7790

Intro

Compare those specs to the Radeon HD 7790, which features a clock speed of 1000 MHz and a GDDR5 memory speed of 1500 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is made up of 896 SPUs, 56 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7790		85 Watts
	Difference: 30 Watts (55%)

Memory Bandwidth

Performance-wise, the Radeon HD 7790 should in theory be quite a bit better than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 80000 (500%)

Texel Rate

The Radeon HD 7790 should be much (approximately 192%) faster with regards to texture filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 36800 (192%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7790 is the winner, and very much so. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 11200 (233%)

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 maximum amount of data (in units of MB per second) that can be transported over the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

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