Should I add a separate audio card? I am using a production premium and for now I using the on board sound card which is a 5.1 Realtek. First I am no pro but do like editing events etc. Is there advantage dis-advantage? Also will be using Audition. If it is better to get audio card which one?
Many on-board audio chips are very good, so long as their driver support is also very good. If not, then ASIO4All is often a viable option.
Separate audio cards, and devices might offer advantages to some users, but all are not trouble-free. I would test extensively your Realtek chip, and see how things go. If you have any issues (PrPro and Audition), then consider and test the free ASIO4All driver. If you are still coming up short, then perhaps something from M-Audio, or similar, would be a good investment - but only if your Realtek chip does not do the job for you.
Just my observations from my personal experiences.
I think for your work, the built-in motherboard sound is perfectly adequate. Spend your money elsewhere.