UICollectionview Scrolling choppy when loading cells

Tick on clip subviews and opaque in attributes inspector and tick off paging enabled.

Load your images using NSURLConnection's sendAsynchronousRequest:queue:completionHandler:

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
    [cell.imageView setImage:[UIImage imageWithData:data]];
}];

I would assume the "choppyness" is coming from the UIImage allocation, not anything with the dequeueReusableCellWithReuseIdentifier method. I'd try doing the image allocation on a background thread and see if that makes things a little more buttery.

-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
  mycell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void) {
     // Load image on a non-ui-blocking thread
    UIImage *image = [[UIImage imageWithCGImage:[alassetList objectAtIndex:indexpath.row] thumbnail]];

    dispatch_sync(dispatch_get_main_queue(), ^(void) {
        // Assign image back on the main thread
        mycell.imageView.image = image;
    });
  });

  return mycell;
}

More details can be found here: https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/Multithreading/Introduction/Introduction.html

So anybody having scrolling issues should do this

add these 2 lines after your dequeue

cell.layer.shouldRasterize = YES;
cell.layer.rasterizationScale = [UIScreen mainScreen].scale;