GeForce GT 420 vs Radeon HD 4850 1GB

Intro

Compare all that to the Radeon HD 4850 1GB, which has core speeds of 625 MHz on the GPU, and 993 MHz on the 1024 MB of GDDR4 RAM. It features 800(160x5) SPUs as well as 40 TAUs 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 1GB		110 Watts
	Difference: 60 Watts (120%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 4850 1GB will be 121% quicker than the GeForce GT 420 overall, due to its greater data rate. (explain)

Radeon HD 4850 1GB		63552 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 34752 (121%)

Texel Rate

The Radeon HD 4850 1GB is quite a bit (approximately 346%) better at AF than the GeForce GT 420. (explain)

Radeon HD 4850 1GB		25000 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 19400 (346%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 4850 1GB is superior to the GeForce GT 420, and very much so. (explain)

Radeon HD 4850 1GB		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 data (in units of MB per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the 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 write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill 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 reach the maximum fill rate.