Radeon R9 M265X vs Radeon R9 M275X

Intro

Compare all that to the Radeon R9 M275X, which features a clock frequency of 900 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It features 640 SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have the exact same bandwidth, so in theory they should have the same performance. (explain)

Texel Rate

The Radeon R9 M275X will be a lot (more or less 57%) more effective at anisotropic filtering than the Radeon R9 M265X. (explain)

Radeon R9 M275X		36000 Mtexels/sec
Radeon R9 M265X		23000 Mtexels/sec
	Difference: 13000 (57%)

Pixel Rate

The Radeon R9 M275X will be much (about 57%) better at FSAA than the Radeon R9 M265X, and should be able to handle higher resolutions while still performing well. (explain)

Radeon R9 M275X		14400 Mpixels/sec
Radeon R9 M265X		9200 Mpixels/sec
	Difference: 5200 (57%)

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 megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better 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 texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.