Radeon HD 4650 1GB vs Radeon HD 7870

Intro

Compare all that to the Radeon HD 7870, which features core speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. 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 1GB		55 Watts
Radeon HD 7870		175 Watts
	Difference: 120 Watts (218%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7870 should perform much faster than the Radeon HD 4650 1GB in general. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 131200 (586%)

Texel Rate

The Radeon HD 7870 is much (about 317%) faster with regards to anisotropic filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 60800 (317%)

Pixel Rate

The Radeon HD 7870 will be much (approximately 567%) faster with regards to AA than the Radeon HD 4650 1GB, and also capable of handling higher resolutions while still performing well. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 4650 1GB		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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be moved over the external memory interface in a second. The number is worked out by multiplying the bus width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.