I recently update my private server hosted on my laptop, to 1.7.4 and also my client. I was playing on the server by myself and at times I am getting 66 chunk updates but average about 40, (on my client). It runs perfectly fine, however when it updates I go from a sudden 30fps to maybe 1 or 2. I Have no idea why this happens. There is also no red bars in my Server Screen.
Attached is a screenshot with 70 chunk updates.