Radeon HD 4650 1GB vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which uses a 28 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 RAM is set to run at a speed of 1200 MHz on this particular card. It features 1280 SPUs along with 80 Texture Address Units and 32 ROPs.

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

Performance-wise, the Radeon HD 7870 should theoretically be quite a bit better than the Radeon HD 4650 1GB overall. (explain)

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

Texel Rate

The Radeon HD 7870 will be much (about 317%) better at 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 is quite a bit (about 567%) better at FSAA than the Radeon HD 4650 1GB, and also will be able to handle higher screen resolutions more effectively. (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: Bandwidth is the largest amount of data (measured in MB per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

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