Low Windows Experience Index Processor score

I have sony Vaio VPCEC290X before Windows Experience Index was 5.1 but now it reduced to 3.5 i have update to latest bios a i have check power settings cleaned laptop dust also but the score is still 3.5 what might be the problem i have contact sony care also they checked and told nothing problem with your hardware

the problem with your updated bios.
this problems was also occurs for me on my desktop when i update my bios
Before update my score was 4.8 and after it dropped to 3.3 so i downgraded my bios.

Try to Downgrade your bios Version.