Radeon HD 4830 512MB vs Radeon HD 4850 1GB

Intro

Compare those specifications to the Radeon HD 4850 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR4 RAM runs at a frequency of 993 MHz on this particular card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 512MB		95 Watts
Radeon HD 4850 1GB		110 Watts
	Difference: 15 Watts (16%)

Memory Bandwidth

The Radeon HD 4850 1GB should theoretically be a small bit faster than the Radeon HD 4830 512MB in general. (explain)

Radeon HD 4850 1GB		63552 MB/sec
Radeon HD 4830 512MB		57600 MB/sec
	Difference: 5952 (10%)

Texel Rate

The Radeon HD 4850 1GB is quite a bit (more or less 36%) faster with regards to anisotropic filtering than the Radeon HD 4830 512MB. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
Radeon HD 4830 512MB		18400 Mtexels/sec
	Difference: 6600 (36%)

Pixel Rate

The Radeon HD 4850 1GB is a bit (more or less 9%) faster with regards to full screen anti-aliasing than the Radeon HD 4830 512MB, and will be able to handle higher screen resolutions better. (explain)

Radeon HD 4850 1GB		10000 Mpixels/sec
Radeon HD 4830 512MB		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 max amount of data (counted in megabytes per second) that can be moved over the external memory interface within a second. It is worked out by multiplying the bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.