GeForce GT 640 DDR3 vs Radeon HD 7870

Intro

Compare those specifications to the Radeon HD 7870, which makes use of a 28 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 memory is set to run at a speed of 1200 MHz on this specific model. It features 1280 SPUs as well as 80 TAUs and 32 ROPs.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 7870		6230 points
GeForce GT 640 DDR3		1560 points
	Difference: 4670 (299%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7870		175 Watts
	Difference: 110 Watts (169%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7870 should perform much faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7870		153600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 96576 (169%)

Texel Rate

The Radeon HD 7870 should be quite a bit (more or less 178%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)

Radeon HD 7870		80000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 51200 (178%)

Pixel Rate

The Radeon HD 7870 is a lot (approximately 122%) more effective at anti-aliasing than the GeForce GT 640 DDR3, and able to handle higher resolutions better. (explain)

Radeon HD 7870		32000 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 17600 (122%)

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 information (measured in MB per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. 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 rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.