> Memory addressing Current 64-bit CPUs generally don't go past 52-bits of memory addressing. That's 4.5 Petabytes and they still have 12 doublings to go. It i

> Memory addressing Current 64-bit CPUs generally don't go past 52-bits of memory addressing. That's 4.5 Petabytes and they still have 12 doublings to go. It is also possible to have memory addressing wider than your CPU. 8-bit chips almost universally did this. Even the P4 had 36 bits on a 32-bit CPU. > Multi-byte processing You can have wider vector load instructions without affecting the main CPU width > Gaming/simulation Legit point. IBM POWER has 128-bit IEEE floats and decimal hardware coprocessors, but I believe the rest of the CPU is still 64-bits wide. The easiest solution here is to allow those 256/512 vector units to do 128-bit floats in addition to 64-bit floats. > Hashing If you have a hashtable that needs 128-bits due to collisions, it is a MASSIVE table. It definitely won't be fitting into cache and probably not into RAM. A few extra instructions (or even a hundred extra instructions) to do the math with two 64-bit segments will still be nothing compared to the thousands of cycles reaching out to RAM or the millions/billions of cycles reaching out to the disk.