Radeon HD 3870 512MB vs Radeon R7 240

Intro

Compare those specifications to the Radeon R7 240, which has GPU core speed of 730 MHz, and 2048 MB of DDR3 RAM running at 900 MHz through a 128-bit bus. It also is made up of 320 Stream Processors, 20 TAUs, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon R7 240		30 Watts
Radeon HD 3870 512MB		106 Watts
	Difference: 76 Watts (253%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 3870 512MB will be 100% quicker than the Radeon R7 240 overall, because of its greater data rate. (explain)

Radeon HD 3870 512MB		57600 MB/sec
Radeon R7 240		28800 MB/sec
	Difference: 28800 (100%)

Texel Rate

The Radeon R7 240 should be a little bit (about 18%) better at AF than the Radeon HD 3870 512MB. (explain)

Radeon R7 240		14600 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 2200 (18%)

Pixel Rate

The Radeon HD 3870 512MB will be a lot (more or less 112%) more effective at anti-aliasing than the Radeon R7 240, and capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 3870 512MB		12400 Mpixels/sec
Radeon R7 240		5840 Mpixels/sec
	Difference: 6560 (112%)

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 (counted in megabytes per second) that can be transferred past the external memory interface in one second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 texture map elements (texels) that can be applied in one second. This figure is worked out by multiplying the total number 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 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 video card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). 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 ability to get to the maximum fill rate.