Radeon HD 4790 vs Radeon HD 4870 512MB

Intro

Compare those specifications to the Radeon HD 4870 512MB, which uses a 55 nm design. AMD has clocked the core speed at 750 MHz. The GDDR5 memory works at a frequency of 900 MHz on this model. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4870 512MB should theoretically perform a bit faster than the Radeon HD 4790 overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 12800 (13%)

Texel Rate

The Radeon HD 4870 512MB should be a lot (approximately 56%) faster with regards to anisotropic filtering than the Radeon HD 4790. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 10800 (56%)

Pixel Rate

The Radeon HD 4870 512MB will be quite a bit (about 25%) more effective at anti-aliasing than the Radeon HD 4790, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 4870 512MB		12000 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 2400 (25%)

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 (counted in megabytes per second) that can be moved across the external memory interface within a second. It is calculated by multiplying the interface width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units of the card by the core 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 per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units 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 output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.