Radeon HD 4890 1GB vs Radeon HD 7850

Intro

Compare those specs to the Radeon HD 7850, which has clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1024 SPUs as well as 64 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 60 Watts (46%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7850 should in theory be quite a bit superior to the Radeon HD 4890 1GB in general. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 28800 (23%)

Texel Rate

The Radeon HD 7850 is a lot (about 38%) more effective at AF than the Radeon HD 4890 1GB. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 15040 (38%)

Pixel Rate

The Radeon HD 7850 should be a lot (about 72%) more effective at full screen anti-aliasing than the Radeon HD 4890 1GB, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 11520 (72%)

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 megabytes per second) that can be transported over the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total 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 processed in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called 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 of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.