Forge: 10.13.0.1208
Mekanism 7.1.0.90

Using Mekanism 7.1 on a server has more than doubled the memory usage. Removing Mekanism or going back to 7.0.0.75 reverts memory usage back to normal.

Not really sure how to report this one

mekanism.api.Coord4D seems to spike up to about 140 000 000 bytes from time to time. But not sure it is that.
Also getting TPS in the range of 0.4 - 5.
Removing Mekanism returns it to 20

Edit: How I wish there was an OPIS for 1.7.10

Mind using VisualVM to show where memory usage gets high? I can't do anything unless I'm sure it's a Mekanism issue and I know what is hogging your memory.

I'll try

Aha! Transporter/sorter usage should also be extremely toned down for the v8 update.

Found the issue. A logistical transporter kept trying to sort items that couldnt fit anywhere, resulting in an overflow of about 1000 stacks. Breaking all transporter and the sorter solved the issue.

Something is seriously wrong with the Logistical Transporter. I think it now creates items if it can't sort them. Almost crashed my server with 4000+ stacks of coal.
Edit: Also: 1000 stacks of Certus Quartz