GeForce GT 640 DDR3 vs Radeon R9 M395X

Intro

Compare all of that to the Radeon R9 M395X, which has a clock speed of 723 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit memory bus, and makes use of a 28 nm design. It is made up of 2048 SPUs, 128 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
Radeon R9 M395X		125 Watts
	Difference: 60 Watts (92%)

Memory Bandwidth

In theory, the Radeon R9 M395X will be 181% quicker than the GeForce GT 640 DDR3 in general, because of its higher data rate. (explain)

Radeon R9 M395X		160000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 102976 (181%)

Texel Rate

The Radeon R9 M395X is a lot (approximately 221%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon R9 M395X		92544 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 63744 (221%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon R9 M395X is superior to the GeForce GT 640 DDR3, and very much so. (explain)

Radeon R9 M395X		23136 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 8736 (61%)

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 MB per second) that can be transferred across the external memory interface in a second. The number is calculated by multiplying the bus width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the card's 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 rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.