There are currently seven specifications for graphics cards - G1, G2, G3, G4, G5, G6 and G7. Graphics cards of the G7 classification have a bandwidth of 128 GB/s (GigaByte per Second) and more, without an upper limit today.
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The commission wants to stop dedicated graphics cards of group G7 from going above 320 GB/s - that is in theory a memory bus at 384-bit connected to memory operating at 6667 MHz or 512-bit with 5001 MHz. This is definitely within reach for the next generation graphics cards. Radeon HD 7970 GHz Edition currently has a bandwidth of 288 GB/s with a 384-bit memory bus and 6000 MHz memory. For notebooks the limit will be only 225 GB/s.
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Earlier today there were talk about the new restrictions going into effect in early 2013, but now it looks like it will be 2014. This will put nearly unrealistic demands on both AMD and Nvidia. Besides the fact the standardization is not very logical since memory bandwidth does not translate into performance that easily we see it as a great obstacle for future graphics cards...