Radeon HD 4770 vs Radeon HD 4850 2GB

Intro

Compare all of that to the Radeon HD 4850 2GB, which comes with core clock speeds of 625 MHz on the GPU, and 993 MHz on the 2048 MB of GDDR4 RAM. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 30 Watts (38%)

Memory Bandwidth

In theory, the Radeon HD 4850 2GB should be 24% faster than the Radeon HD 4770 overall, because of its higher bandwidth. (explain)

Radeon HD 4850 2GB		63552 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 12352 (24%)

Texel Rate

The Radeon HD 4850 2GB should be just a bit (more or less 4%) more effective at anisotropic filtering than the Radeon HD 4770. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 1000 (4%)

Pixel Rate

The Radeon HD 4770 is a little bit (approximately 20%) faster with regards to full screen anti-aliasing than the Radeon HD 4850 2GB, and should be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 4850 2GB		10000 Mpixels/sec
	Difference: 2000 (20%)

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 (in units of MB per second) that can be transferred past the external memory interface in a second. It's worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.