GeForce GT 240 GDDR5 1GB vs GeForce GT 420

Intro

Compare those specifications to the GeForce GT 420, which has a core clock frequency of 700 MHz and a GDDR3 memory speed of 900 MHz. It also features a 128-bit memory bus, and makes use of a 40 nm design. It features 48 SPUs, 8 TAUs, and 4 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 420		50 Watts
GeForce GT 240 GDDR5 1GB		70 Watts
	Difference: 20 Watts (40%)

Memory Bandwidth

In theory, the GeForce GT 240 GDDR5 1GB should be quite a bit faster than the GeForce GT 420 in general. (explain)

GeForce GT 240 GDDR5 1GB		54400 MB/sec
GeForce GT 420		28800 MB/sec
	Difference: 25600 (89%)

Texel Rate

The GeForce GT 240 GDDR5 1GB is quite a bit (approximately 214%) more effective at AF than the GeForce GT 420. (explain)

GeForce GT 240 GDDR5 1GB		17600 Mtexels/sec
GeForce GT 420		5600 Mtexels/sec
	Difference: 12000 (214%)

Pixel Rate

The GeForce GT 240 GDDR5 1GB should be a lot (about 57%) better at FSAA than the GeForce GT 420, and should be able to handle higher screen resolutions without losing too much performance. (explain)

GeForce GT 240 GDDR5 1GB		4400 Mpixels/sec
GeForce GT 420		2800 Mpixels/sec
	Difference: 1600 (57%)

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 (in units of megabytes per second) that can be transferred across the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher 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 are applied in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.