GeForce GT 640 DDR3 vs Radeon HD 7870 XT

Intro

Compare those specifications to the Radeon HD 7870 XT, which features a clock frequency of 925 MHz and a GDDR5 memory speed of 1500 MHz. It also features a 256-bit memory bus, and uses a 28 nm design. It features 1536 SPUs, 96 Texture Address Units, and 32 Raster Operation 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 XT		6390 points
GeForce GT 640 DDR3		1560 points
	Difference: 4830 (310%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7870 XT		185 Watts
	Difference: 120 Watts (185%)

Memory Bandwidth

The Radeon HD 7870 XT should in theory perform much faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7870 XT		192000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 134976 (237%)

Texel Rate

The Radeon HD 7870 XT will be much (more or less 208%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 60000 (208%)

Pixel Rate

The Radeon HD 7870 XT will be quite a bit (approximately 106%) faster with regards to FSAA than the GeForce GT 640 DDR3, and should be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7870 XT		29600 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 15200 (106%)

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 information (in units of megabytes per second) that can be moved over the external memory interface within a second. It's worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, 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 number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total 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 in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.