SEO advice needed

[goxy63]

I was not quite sure what is better so I kept booth forums where each story is thread and one big thread where each story is one post

Now I dont have same content on two places, only name of that big thread and new forums are similar

For example

Old big thread is named "Sample Thread" and name of forums is "Sample thread - New" [only "new" is added]

Now after some time I got 90% less visitors on that big thread full with posts, but on other side there is insignificant improvement with new forums where visitors start to come...

Any advice, one big thread or one big forum with similar content... what would be better in order to have more visitors?

Ty