Windows thin wallet is slow

Do not know why, but the walletlite in Windows is very slow to sync data, it takes a very long time; at the same time, I do not know why it consume CPU a lot. 

The thin wallet just need to sync the head of blocks, and why it needs lots of CPU resource? does it also mine? I do not want to have that, I want the thin wallet only quickly sync and let me know my wallet status. 