Both mean "more than"
But the usage is different.
보다 is used to compare any 2 things with each other. The word preceding 보다 is the standard from which a comparison will be made. This grammar point corresponds to “More/Less…Than” “-er…Than”. Also note that the word 더 are generally used together with 보다, but can be omitted.
ex)
주스보다 물을 (더) 좋아해요. = I like water more than juice/I prefer water to juice.
어제보다 오늘이 따뜻하다. = Today is warmer than yesterday.
아이패드보다 킨들을 더 좋아합니다. = I prefer the Kindle to the I-pad
그 여자보다 그 남자가 옷을 잘 입어요. = That man is wearing better clothes than that woman.
이상으로 is used as meaning of "beyond, past, more than; further"
It does not require comparison of 2 things.
ex)
그는 필요 이상으로 상품을 주문했다. = He ordered products more than needs.
나는 그녀를 친구 이상으로 좋아했었다. = I loved her as more than a friend.
나는 그가 보통 이상으로 머리가 좋다고 확신했다. = I was convinced that he was brighter than average.
농악에서는 24명 이상으로 구성된 전문 농악단이 함께 공연을 한다.= In nongak, professional bands of 24 or more performers play together.