GeForce GT 640 DDR3 vs GeForce GTX 285 2GB

Intro

Compare all that to the GeForce GTX 285 2GB, which features a core clock frequency of 648 MHz and a GDDR3 memory frequency of 1242 MHz. It also features a 512-bit bus, and uses a 55 nm design. It is comprised of 240 SPUs, 80 TAUs, and 32 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
GeForce GTX 285 2GB		204 Watts
	Difference: 139 Watts (214%)

Memory Bandwidth

The GeForce GTX 285 2GB should in theory perform a lot faster than the GeForce GT 640 DDR3 overall. (explain)

GeForce GTX 285 2GB		158976 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 101952 (179%)

Texel Rate

The GeForce GTX 285 2GB is a lot (about 80%) more effective at AF than the GeForce GT 640 DDR3. (explain)

GeForce GTX 285 2GB		51840 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 23040 (80%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GTX 285 2GB is the winner, and very much so. (explain)

GeForce GTX 285 2GB		20736 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 6336 (44%)

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 max amount of data (measured in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better 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 number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

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