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 frequency at 625 MHz. The GDDR3 memory works at a speed of 993 MHz on this particular card. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

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

Theoretically speaking, the Radeon HD 4850 512MB should perform much faster than the Radeon HD 4770 overall. (explain)

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

Texel Rate

The Radeon HD 4850 512MB is a bit (approximately 4%) better at anisotropic filtering than the Radeon HD 4770. (explain)

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

Pixel Rate

The Radeon HD 4770 should be a small bit (more or less 20%) more effective at full screen anti-aliasing than the Radeon HD 4850 512MB, and capable of handling higher resolutions more effectively. (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 maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface in one second. It's worked out by multiplying the card's bus width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 once 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, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

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