GeForce GT 640 DDR3 vs Radeon RX 6800

Intro

Compare those specifications to the Radeon RX 6800, which has core clock speeds of 1700 MHz on the GPU, and 2000 MHz on the 16384 MB of GDDR6 memory. It features 3840 SPUs along with 240 TAUs and 96 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon RX 6800		250 Watts
	Difference: 185 Watts (285%)

Memory Bandwidth

Theoretically speaking, the Radeon RX 6800 is 819% faster than the GeForce GT 640 DDR3 overall, because of its greater data rate. (explain)

Radeon RX 6800		524288 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 467264 (819%)

Texel Rate

The Radeon RX 6800 will be much (approximately 1317%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon RX 6800		408000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 379200 (1317%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon RX 6800 is superior to the GeForce GT 640 DDR3, by a large margin. (explain)

Radeon RX 6800		163200 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 148800 (1033%)

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 (counted in megabytes per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 are processed in one second. This figure is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the card will be at 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 that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of 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.