Radeon HD 4850 1GB vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which has GPU core speed of 860 MHz, and 2048 MB of GDDR5 memory set to run at 1200 MHz through a 256-bit bus. It also is made up of 1024 Stream Processors, 64 TAUs, and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
Radeon HD 7850		130 Watts
	Difference: 20 Watts (18%)

Memory Bandwidth

The Radeon HD 7850 should in theory perform much faster than the Radeon HD 4850 1GB in general. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 90048 (142%)

Texel Rate

The Radeon HD 7850 will be quite a bit (approximately 120%) faster with regards to anisotropic filtering than the Radeon HD 4850 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 30040 (120%)

Pixel Rate

The Radeon HD 7850 will be quite a bit (about 175%) more effective at AA than the Radeon HD 4850 1GB, and should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 17520 (175%)

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 (counted in MB per second) that can be transferred past the external memory interface in one second. It's calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen 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 texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units 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 output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.