Gmail- 1st time testing

I've try to send two mail to test the GMail service, here's the result in one hour after that, seems not very reliable (or efficient)

#1, with a 3.07MB attachment, send to my e-mail in reallusion.com.tw, didn't receive it.

#2, with a 4.7MB attachment, send to both gmail.com and reallusion.com.tw, only reallusion.com.tw got it.

In its F.A.Q., it might be able to support pop3 in the future, it's better to support. I don't know what can I do with this big, but web-based e-mail.