GeForce GTS 450 vs Radeon HD 4790

Intro

Compare all that to the Radeon HD 4790, which makes use of a 55 nm design. AMD has clocked the core frequency at 600 MHz. The GDDR5 memory runs at a frequency of 800 MHz on this model. It features 640(128x5) SPUs as well as 32 TAUs and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon HD 4790 should in theory perform quite a bit faster than the GeForce GTS 450 in general. (explain)

Radeon HD 4790		102400 MB/sec
GeForce GTS 450		57728 MB/sec
	Difference: 44672 (77%)

Texel Rate

The GeForce GTS 450 is quite a bit (approximately 31%) better at anisotropic filtering than the Radeon HD 4790. (explain)

GeForce GTS 450		25056 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 5856 (31%)

Pixel Rate

The GeForce GTS 450 is much (more or less 31%) more effective at AA than the Radeon HD 4790, and will be able to handle higher resolutions while still performing well. (explain)

GeForce GTS 450		12528 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 2928 (31%)

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 information (measured in MB per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster 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 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 the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of 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 rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.