GeForce GT 420 vs Radeon HD 4850 512MB

Intro

Compare those specifications to the Radeon HD 4850 512MB, which comes with clock speeds of 625 MHz on the GPU, and 993 MHz on the 512 MB of GDDR3 RAM. 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)

GeForce GT 420		50 Watts
Radeon HD 4850 512MB		110 Watts
	Difference: 60 Watts (120%)

Memory Bandwidth

Performance-wise, the Radeon HD 4850 512MB should in theory be much better than the GeForce GT 420 overall. (explain)

Radeon HD 4850 512MB		63552 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 34752 (121%)

Texel Rate

The Radeon HD 4850 512MB will be quite a bit (approximately 346%) faster with regards to AF than the GeForce GT 420. (explain)

Radeon HD 4850 512MB		25000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 19400 (346%)

Pixel Rate

The Radeon HD 4850 512MB is much (about 257%) better at full screen anti-aliasing than the GeForce GT 420, and will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 4850 512MB		10000 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 7200 (257%)

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: Bandwidth is the max amount of information (measured in MB per second) that can be transferred past the external memory interface within a second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card 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 Render Output Units 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 fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.