@autoreleasepool without ARC?
From http://clang.llvm.org/docs/AutomaticReferenceCounting.html#autoreleasepool:
@autoreleasepoolmay be used in non-ARC translation units, with equivalent semantics.
LLVM 3.0's
@autoreleasepool { ... }is much faster than NSAutoreleasePool if your deployment target is new enough. No ARC required. (…) always works, but it's faster with deployment target of OS X 10.7 or iOS 5.0.
So you may use @autoreleasepool regardless of ARC, and it’ll be faster than NSAutoreleasePool on OS X v10.7+ and iOS 5.0+.