Radeon HD 4650 512MB vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which has core clock speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1280 SPUs as well as 80 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7870		175 Watts
	Difference: 120 Watts (218%)

Memory Bandwidth

In theory, the Radeon HD 7870 should perform much faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 137600 (860%)

Texel Rate

The Radeon HD 7870 will be quite a bit (about 317%) more effective at texture filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 60800 (317%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 7870 is the winner, by a large margin. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 27200 (567%)

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 maximum amount of data (counted in megabytes per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one 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 Raster Operations Pipelines 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.