Radeon HD 4870 1GB vs Radeon HD 7850

Intro

Compare all of that to the Radeon HD 7850, which features a GPU core clock speed of 860 MHz, and 2048 MB of GDDR5 memory running at 1200 MHz through a 256-bit bus. It also is comprised of 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 20 Watts (15%)

Memory Bandwidth

Performance-wise, the Radeon HD 7850 should theoretically be quite a bit better than the Radeon HD 4870 1GB overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 38400 (33%)

Texel Rate

The Radeon HD 7850 is quite a bit (about 83%) better at texture filtering than the Radeon HD 4870 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 25040 (83%)

Pixel Rate

The Radeon HD 7850 should be quite a bit (about 129%) faster with regards to full screen anti-aliasing than the Radeon HD 4870 1GB, and also should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 15520 (129%)

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 (measured in megabytes per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total number of texture units 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 applied in a second.

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