C:\test>junk -B=4 < 1gb.dat
Found 6559 matches in 10.778 seconds using 4 kb reads

C:\test>junk -B=64 < 1gb.dat
Found 6559 matches in 10.567 seconds using 64 kb reads

C:\test>junk -B=256 < 1gb.dat
Found 6559 matches in 10.574 seconds using 256 kb reads

C:\test>junk -B=1024 < 1gb.dat
Found 6559 matches in 10.938 seconds using 1024 kb reads

C:\test>junk -B=4096 < 1gb.dat
Found 6559 matches in 10.995 seconds using 4096 kb reads

C:\test>junk -B=65536 < 1gb.dat
Found 6559 matches in 12.533 seconds using 65536 kb reads