GeForce GT 420 vs Radeon HD 3690/3830

Intro

Compare those specs to the Radeon HD 3690/3830, which features core clock speeds of 668 MHz on the GPU, and 828 MHz on the 256 MB of GDDR3 memory. It features 320(64x5) SPUs as well as 16 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 3690/3830		75 Watts
	Difference: 25 Watts (50%)

Memory Bandwidth

The GeForce GT 420 should theoretically perform just a bit faster than the Radeon HD 3690/3830 overall. (explain)

GeForce GT 420		28800 MB/sec
Radeon HD 3690/3830		26496 MB/sec
	Difference: 2304 (9%)

Texel Rate

The Radeon HD 3690/3830 will be a lot (about 91%) faster with regards to texture filtering than the GeForce GT 420. (explain)

Radeon HD 3690/3830		10688 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 5088 (91%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 3690/3830 is a better choice, by far. (explain)

Radeon HD 3690/3830		10688 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 7888 (282%)

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 (measured in MB per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 applied per second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on 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 get to the max fill rate.