Geforce GTX 680 vs Radeon HD 4650 512MB

Intro

Compare those specs to the Radeon HD 4650 512MB, which comes with core speeds of 600 MHz on the GPU, and 500 MHz on the 512 MB of DDR2 RAM. It features 320(64x5) SPUs as well as 32 Texture Address Units and 8 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Geforce GTX 680		195 Watts
	Difference: 140 Watts (255%)

Memory Bandwidth

In theory, the Geforce GTX 680 should be 1102% faster than the Radeon HD 4650 512MB overall, due to its higher data rate. (explain)

Geforce GTX 680		192256 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 176256 (1102%)

Texel Rate

The Geforce GTX 680 is much (about 571%) more effective at AF than the Radeon HD 4650 512MB. (explain)

Geforce GTX 680		128768 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 109568 (571%)

Pixel Rate

The Geforce GTX 680 will be quite a bit (approximately 571%) better at AA than the Radeon HD 4650 512MB, and also will be capable of handling higher screen resolutions without slowing down too much. (explain)

Geforce GTX 680		32192 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 27392 (571%)

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 transferred across the external memory interface in a second. The number is worked out by multiplying the bus width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better 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 amount of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total number of texture units of the card by the core clock 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 applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number 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 rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.