GeForce GT 640 DDR3 vs Radeon HD 7770

Intro

Compare all that to the Radeon HD 7770, which features core clock speeds of 1000 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 RAM. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

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 7770		3180 points
GeForce GT 640 DDR3		1560 points
	Difference: 1620 (104%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7770		80 Watts
	Difference: 15 Watts (23%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7770 will be 26% faster than the GeForce GT 640 DDR3 in general, because of its higher bandwidth. (explain)

Radeon HD 7770		72000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 14976 (26%)

Texel Rate

The Radeon HD 7770 will be quite a bit (about 39%) more effective at AF than the GeForce GT 640 DDR3. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 11200 (39%)

Pixel Rate

The Radeon HD 7770 will be a bit (more or less 11%) faster with regards to anti-aliasing than the GeForce GT 640 DDR3, and able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 1600 (11%)

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 over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 again. If 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, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed 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 this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.