Wanna know the answer?
There's NO FREAKING DIFFERENCE whatsoever but unfortunately to some people (you know who you are), there's a difference.
Let me share with you my personal story of when I first found out about this. This incident happened a couple of years ago. I was looking for simple to eat which was easy to prepare and fast - so I went to this stall and ordered me a plate of Kuay Teow Goreng. To my amazement, this fella asked me, "awak nak Kuay Teow Goreng atau Char Kuay Teow?" and I'm like... "bukan kedua² tu sama ke?" ("ain't both the same thing?"). He then told me that Kuay Teow Goreng is dry and Char Kuay Teow is wet (one or the other - I don't really remember which is which) and I was like blur for a brief moment.
Hello...!!! "Char Kuay Teow" already means Fried Kuay Teow a.k.a. Kuay Teow Goreng so if you want to make it wet, freaking call it Kuay Teow Goreng BASAH instead. Next time find out the translation from the Chinese people before going about confusing other people. When I told them the actual meaning of it which basically means the same, they said nothing and I didn't wanna waste my time trying to explain any further.
Nowadays if I happen to order that dish, I'd have to ask them which one is which or they would probably mess up my order.