From the Mobil Website
Mobil 1 0W-30
SAE Grade 0W-30
Viscosity @ 100ºC, cSt (ASTM D445) 10.9
Viscosity, @ 40ºC, cSt (ASTM D445) 62.9
Mobil 1 10W-30
SAE Grade 10W-30
Viscosity @ 100ºC, cSt (ASTM D445) 10.1
Viscosity, @ 40ºC, cSt (ASTM D445) 63.2
Looks like 0w-30 has a higher viscosity at 100 degrees C. albeit marginal.
Mobil 1 0W-30
SAE Grade 0W-30
Viscosity @ 100ºC, cSt (ASTM D445) 10.9
Viscosity, @ 40ºC, cSt (ASTM D445) 62.9
Mobil 1 10W-30
SAE Grade 10W-30
Viscosity @ 100ºC, cSt (ASTM D445) 10.1
Viscosity, @ 40ºC, cSt (ASTM D445) 63.2
Looks like 0w-30 has a higher viscosity at 100 degrees C. albeit marginal.