What is UDMA CRC Error Count?

Hello,

My macbook retina 15" was freezing and sometimes it couldn't open so i gave it to the service and they said that my ssd has problems. Because of sdd pricei is too high i couldnt afford it and give my laptop back. I checked my ssd with an app called Drivedx. It say "UDMA CRC Error Count", what is this problem? By the way they also clean my macs interior, they say it was so dusty. I noticed that freezing was nearly gone. However, as i use my laptop on music stage, im afraid of it freeze on stage. What should i do? Is there any app that i can check if my ssd is OK or NOt?