Dude? What are you talking about? How does that end it? The only bus that review mentions is the memory bus:
|X1600 series and its disappointing to see this is the case. Rather than stick with the 256bit bus used by the X1800 the X1600 uses a 128bit bus…this could severely hamper the performance of the card
the x1800 series has always had a 512bit ring bus (<-> 256), 256 bit memory bus, and the x1600 has always had a 256bit (<-> 128) ring bus, 128 memory. Btw if you want to become more knowledgeable about 3d hardware, I suggest you start reading B3D.
|Both RV530 and RV515 utilise 128-bit memory buses, given that they are both addressing the lower end of the graphics market, however while the external bus widths are the same, internally they both have different buses. RV530 adopts a similar Ring Bus mechanism as R520, but in this case the alternate direction ring buses are both 128-bit in width as opposed to 256-bit, with 4 memory controllers allowing for 32-bit access granularity. Due to the size of the ring bus requirements, RV515 utilises a more traditional crossbar mechanism, although unlike previous Radeons 4 controllers are used, again giving 32-bit granularity for the 4 memory channels, which allows for more flexibility with HyperMemory configurations. Other memory optimisations featured in R520, such as fully associative caches, Hierarchical Z buffer test, Z compression and anti-aliasing colour compression are all present on both RV530 and RV515.