Radeon HD 4770 vs Radeon HD 4850 512MB

Intro

Compare that to the Radeon HD 4850 512MB, which makes use of a 55 nm design. AMD has clocked the core speed at 625 MHz. The GDDR3 RAM runs at a speed of 993 MHz on this model. It features 800(160x5) SPUs as well as 40 TAUs and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 4850 512MB		110 Watts
	Difference: 30 Watts (38%)

Memory Bandwidth

In theory, the Radeon HD 4850 512MB will be 24% quicker than the Radeon HD 4770 overall, due to its higher bandwidth. (explain)

Radeon HD 4850 512MB		63552 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 12352 (24%)

Texel Rate

The Radeon HD 4850 512MB will be just a bit (approximately 4%) faster with regards to AF than the Radeon HD 4770. (explain)

Radeon HD 4850 512MB		25000 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 1000 (4%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 4770 is a better choice, not by a very large margin though. (explain)

Radeon HD 4770		12000 Mpixels/sec
Radeon HD 4850 512MB		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 max amount of information (measured in megabytes per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at 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 that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.