Radeon HD 4790 vs Radeon HD 6450 (OEM) 1GB

Intro

Compare those specifications to the Radeon HD 6450 (OEM) 1GB, which comes with a core clock speed of 750 MHz and a GDDR5 memory speed of 900 MHz. It also makes use of a 64-bit bus, and makes use of a 40 nm design. It is comprised of 160 SPUs, 8 Texture Address Units, and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

As far as performance goes, the Radeon HD 4790 should in theory be much superior to the Radeon HD 6450 (OEM) 1GB overall. (explain)

Radeon HD 4790		102400 MB/sec
Radeon HD 6450 (OEM) 1GB		28800 MB/sec
	Difference: 73600 (256%)

Texel Rate

The Radeon HD 4790 is quite a bit (approximately 220%) better at AF than the Radeon HD 6450 (OEM) 1GB. (explain)

Radeon HD 4790		19200 Mtexels/sec
Radeon HD 6450 (OEM) 1GB		6000 Mtexels/sec
	Difference: 13200 (220%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 4790 is the winner, by far. (explain)

Radeon HD 4790		9600 Mpixels/sec
Radeon HD 6450 (OEM) 1GB		3000 Mpixels/sec
	Difference: 6600 (220%)

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 (measured in megabytes per second) that can be transferred over the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 amount of texture map elements (texels) that can be processed in one second. This number is calculated by multiplying the total amount of 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 applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.