geekbench 4.0.3 low scores on 2010 macpro 5,1 upgrade 12 core 3.46(x5690)

I just did upgrade 8core2.4 to 12core 3.46 but my 64-bit scores is 16000 which unnormally low,I use Imenu checked the temperature CPU a is 45-58,CPU b is 60-70, why scores getting low like that? normally the scores is 22000 with same OS,CPU,RAM,everything..