The stream processor is usually equipped with a fast, efficient, proprietary memory bus (crossbar switches are now common, multi-buses have been employed in the past). The exact amount of memory lanes is dependent on the market range. As this is written, there are still 64-bit wide interconnections around (entry-level). Most mid-range models use a fast 128-bit crossbar switch matrix (4 or 2 segments), while high-end models deploy huge amounts of memory (actually up to 512 MB) with a slightly slower crossbar that is 256 bits wide. By contrast, standard processors from Intel Pentium to some Athlon 64 have only a single 64-bit wide data bus.