Radeon HD 3850 512MB vs Radeon HD 4850 512MB

Intro

Compare all that to the Radeon HD 4850 512MB, which has a core clock frequency of 625 MHz and a GDDR3 memory frequency of 993 MHz. It also makes use of a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 512MB		75 Watts
Radeon HD 4850 512MB		110 Watts
	Difference: 35 Watts (47%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 512MB should perform a little bit faster than the Radeon HD 3850 512MB overall. (explain)

Radeon HD 4850 512MB		63552 MB/sec
Radeon HD 3850 512MB		52992 MB/sec
	Difference: 10560 (20%)

Texel Rate

The Radeon HD 4850 512MB will be a lot (approximately 134%) better at texture filtering than the Radeon HD 3850 512MB. (explain)

Radeon HD 4850 512MB		25000 Mtexels/sec
Radeon HD 3850 512MB		10688 Mtexels/sec
	Difference: 14312 (134%)

Pixel Rate

The Radeon HD 3850 512MB is a small bit (more or less 7%) better at AA than the Radeon HD 4850 512MB, and also should be capable of handling higher screen resolutions without slowing down too much. (explain)

Radeon HD 3850 512MB		10688 Mpixels/sec
Radeon HD 4850 512MB		10000 Mpixels/sec
	Difference: 688 (7%)

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 megabytes per second) that can be transported across the external memory interface in a second. The number is calculated by multiplying the bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This number 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 graphics card will be at 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 card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.