Chunk Loading Issue

Since the recent update both me, and a friend, have noticed that chunks have been loading significantly slower. What would usually take around 5 seconds to load in all chunks at a 20 chunk render distance now takes upwards of 4 minutes 30 seconds to load a 5 chunk render distance. 

I've done several tests in different environments, all seem to load at the same rate. In addition to this, I have completed 2 reinstalls, updated Java etc.

In addition to this issue, since the update I have had major frame rate and memory usage issues, I usually run close to 200fps, the latest update seems to level out at around 60fps, additionally, pre update was using around 25% of allocated memory, now that is around 50%.

I am presuming this is a bug because I can't see that updated textures etc. would tank my PC to this extent.

Cheers.