Radeon HD 4830 1GB vs Radeon HD 4850 2GB

Intro

Compare those specifications to the Radeon HD 4850 2GB, which features a clock frequency of 625 MHz and a GDDR4 memory frequency of 993 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It is comprised 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 4830 1GB		95 Watts
Radeon HD 4850 2GB		110 Watts
	Difference: 15 Watts (16%)

Memory Bandwidth

In theory, the Radeon HD 4850 2GB is 10% quicker than the Radeon HD 4830 1GB overall, due to its higher data rate. (explain)

Radeon HD 4850 2GB		63552 MB/sec
Radeon HD 4830 1GB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The Radeon HD 4850 2GB is quite a bit (approximately 36%) faster with regards to AF than the Radeon HD 4830 1GB. (explain)

Radeon HD 4850 2GB		25000 Mtexels/sec
Radeon HD 4830 1GB		18400 Mtexels/sec
	Difference: 6600 (36%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon HD 4850 2GB is a better choice, but not by far. (explain)

Radeon HD 4850 2GB		10000 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 800 (9%)

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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be moved over the external memory interface in a second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total texture units by the core clock 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 processed per second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines 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 fill rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.