Compare any two graphics cards:
Radeon HD 4650 512MB vs Radeon HD 7750
IntroThe Radeon HD 4650 512MB has clock speeds of 600 MHz on the GPU, and 500 MHz on the 512 MB of DDR2 RAM. It features 320(64x5) SPUs as well as 32 TAUs and 8 ROPs.
Compare those specs to the Radeon HD 7750, which features clock speeds of 800 MHz on the GPU, and 1125 MHz on the 1024 MB of GDDR5 memory. It features 512 SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
In theory, the Radeon HD 7750 should be 350% faster than the Radeon HD 4650 512MB overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7750 should be much (about 33%) better at texture filtering than the Radeon HD 4650 512MB. (explain)
Pixel RateThe Radeon HD 7750 will be quite a bit (about 167%) better at full screen anti-aliasing than the Radeon HD 4650 512MB, and capable of handling higher resolutions while still performing well. (explain)
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.
Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
Memory Bandwidth: Memory bandwidth is the maximum amount of data (counted in MB per second) that can be moved over the external memory interface in one second. It's worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR memory, the result should 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 AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This figure is worked out by multiplying the total texture units of the card by the core speed of the chip. The better 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 write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.