Radeon HD 3870 512MB vs Radeon HD 4830 1GB

Intro

Compare those specifications to the Radeon HD 4830 1GB, which features a core clock frequency of 575 MHz and a GDDR4 memory frequency of 900 MHz. It also makes use of a 256-bit memory bus, and uses a 55 nm design. It features 640(128x5) SPUs, 32 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4830 1GB		95 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 11 Watts (12%)

Memory Bandwidth

Both cards have the exact same memory bandwidth, so theoretically they should perform exactly the same. (explain)

Texel Rate

The Radeon HD 4830 1GB will be quite a bit (more or less 48%) better at texture filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 4830 1GB		18400 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 6000 (48%)

Pixel Rate

The Radeon HD 3870 512MB should be a lot (approximately 35%) faster with regards to AA than the Radeon HD 4830 1GB, and should be able to handle higher resolutions while still performing well. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon HD 4830 1GB		9200 Mpixels/sec
	Difference: 3200 (35%)

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 largest amount of data (counted in MB per second) that can be transferred across the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.