EqualityTest.m

#import <Foundation/Foundation.h>

@interface Measure : NSObject

+ (NSTimeInterval)timing:(void (^)())blockName;

@end

@implementation Measure 

+ (NSTimeInterval)timing:(void (^)())blockName {
	NSDate *startDate = [NSDate date];
	blockName();
	NSDate *endDate = [NSDate date];
	return [endDate timeIntervalSinceDate:startDate];
}

@end

int main(int argc, char *argv[]) {
	@autoreleasepool {
		NSInteger iterations = 10000;
		
		NSTimeInterval stringDuration = [Measure timing:^(void) {
			NSInteger matches = 0;
			for(int i=0; i<iterations; i++) {
				NSString *className = NSStringFromClass([NSDictionary class]);
				if([className isEqualToString:@"NSDictionary"]) {
					matches++;
				}
			}
		}];
		NSLog(@"%f ms with 'isEqualToString:'", stringDuration);

		NSTimeInterval classMemberDuration = [Measure timing:^(void) {
			NSDictionary *testDict = @{};
			NSInteger matches = 0;
			for(int i=0; i<iterations; i++) {
				if([testDict isMemberOfClass:[NSDictionary class]]) {
					matches++;
				}
			}
		}];
		NSLog(@"%f ms with 'isMemberOfClass:'", classMemberDuration);
		
		NSTimeInterval classDuration = [Measure timing:^(void) {
			Class testClass = [NSDictionary class];
			NSInteger matches = 0;
			for(int i=0; i<iterations; i++) {
				if([NSDictionary class] == testClass) {
					matches++;
				}
			}
		}];
		NSLog(@"%f ms with '(ClassA == ClassB)'", classDuration);
	}
}