iOS Memory allocation questions

[l0uismustdie]

Hello, I am trimming down my app and have been using the Allocations tool to try to track down where most of my memory is being allocated. What I have found are a serious number of allocations to [NSPlaceHolderString:] and [NSPlaceHolderNumber:]. I have gone even further and I believe these are coming from lines like the following:

[returnDict setObject:[memory objectForKey:[NSString stringWithFormat:@"%i",IP]] forKey:@"memory[ip]"];

More specifically I think the [NSString stringWithFormat:] is trouble. Am I correct in this belief and if so is there a better way to handle this type of call?

Thanks