GeForce GT 640 DDR3 vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which has core speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1280 SPUs along with 80 TAUs and 32 Rasterization Operator Units.

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

As far as performance goes, the Radeon HD 7870 should theoretically be quite a bit superior to the GeForce GT 640 DDR3 overall. (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 much (about 178%) faster with regards to texture filtering 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 will be much (about 122%) faster with regards to AA than the GeForce GT 640 DDR3, and able to handle higher screen resolutions while still performing well. (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 data (measured in megabytes per second) that can be transported across the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units by the core 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 processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.