is it necessary to put the i/o shield in the case

[dfcols71]

have build my system but forgot to put the i/o shield ,is it necessary to put it or can we from install it from the outside of the cabinet,i really dont really want to remove the motherboard from from the case standoffs because now the mobo is working after a cumbersome process,especially installing the coolermaster 212 evo,does the sheild protect from dust,also i cant seem to route the 8 pin atx cable to the taking it through the gourmet through the backside of the motherboard in the cabinet into a upper gourmet in case ,to install into 8 pin additional atx connector of mobo.So had to route it above the ram and below the top fan of cabinet into 8 pin aditional atx connector of mobo
I am getting contrasting cpu temp readings,in the uefi setup of mobo it says 46c,but with the asrock exteme tuning softwares which i installed it say 55c both at idle which is correct

 

[techiemaharaj]

It is necessary as it will protect the vital componenets of your pc. You dont want dust and other stuff to create trouble for your pc...

 

[Ishu Gupta]

It also grounds your ports.

And UEFI/BIOS temps are usually lower than OS temps due to different loads.