Fortunately, issue14923 (if accepted) will compensate for the slowdown. On 32-bit Linux, AMD Athlon 64 X2: vanilla old patch fast patch utf-8 'A'*10000 2016 (+3%) 2111 (-2%) 2072 utf-8 '\x80'*10000 383 (+19%) 416 (+9%) 454 utf-8 '\x80'+'A'*9999 1283 (-7%) 1301 (-9%) 1190 utf-8 '\u0100'*10000 383 (+46%) 354 (+58%) 560 utf-8 '\u0100'+'A'*9999 1258 (-1%) 1184 (+5%) 1244 utf-8 '\u0100'+'\x80'*9999 383 (+46%) 354 (+58%) 558 utf-8 '\u8000'*10000 434 (+6%) 388 (+19%) 461 utf-8 '\u8000'+'A'*9999 1262 (-1%) 1180 (+5%) 1244 utf-8 '\u8000'+'\x80'*9999 383 (+46%) 354 (+58%) 559 utf-8 '\u8000'+'\u0100'*9999 383 (+45%) 354 (+57%) 555 utf-8 '\U00010000'*10000 358 (+5%) 361 (+4%) 375 utf-8 '\U00010000'+'A'*9999 1168 (-1%) 1104 (+5%) 1159 utf-8 '\U00010000'+'\x80'*9999 382 (+43%) 307 (+78%) 546 utf-8 '\U00010000'+'\u0100'*9999 382 (+43%) 307 (+79%) 548 utf-8 '\U00010000'+'\u8000'*9999 404 (+13%) 365 (+25%) 458 On 32-bit Linux, Intel Atom N570: vanilla old patch fast patch utf-8 'A'*10000 623 (+1%) 631 (+0%) 631 utf-8 '\x80'*10000 145 (+26%) 165 (+11%) 183 utf-8 '\x80'+'A'*9999 354 (-0%) 358 (-1%) 353 utf-8 '\u0100'*10000 164 (+10%) 156 (+16%) 181 utf-8 '\u0100'+'A'*9999 343 (+1%) 350 (-1%) 348 utf-8 '\u0100'+'\x80'*9999 164 (+10%) 157 (+15%) 181 utf-8 '\u8000'*10000 175 (-1%) 166 (+5%) 174 utf-8 '\u8000'+'A'*9999 349 (+0%) 356 (-2%) 349 utf-8 '\u8000'+'\x80'*9999 164 (+10%) 157 (+15%) 180 utf-8 '\u8000'+'\u0100'*9999 164 (+10%) 157 (+15%) 181 utf-8 '\U00010000'*10000 152 (+7%) 163 (+0%) 163 utf-8 '\U00010000'+'A'*9999 313 (+4%) 332 (-2%) 327 utf-8 '\U00010000'+'\x80'*9999 161 (+11%) 140 (+28%) 179 utf-8 '\U00010000'+'\u0100'*9999 161 (+11%) 139 (+28%) 178 utf-8 '\U00010000'+'\u8000'*9999 160 (+9%) 159 (+9%) 174