Wait, a Lag Message can only happen 10 times per Chunk Load. I bet 430, 67, 512 is part of the Steam Pipe System of Nonotan, right? I bet that Fluid Pipe goes over Chunk Boundaries (z axis) and causes Lag that way, even though that shouldn't be possible due to Anti-Orphan-Chunk-Technology.
Edit: Found another new Solution. "getTileEntityAtSide(byte aSide)" is getting called by almost every crossblock Function in GT. Buffering the Result of that Function and just checking if the TileEntity is still valid (just a !isInvalid() and a Coordinate Check) would reduce the Access to the TileEntity Mappings and increase the CPU Efficency at the cost of a little bit of Memory (not much, just 6 Object Pointers aka Longs per GT TileEntity). Since all vanilla GT Covers, Automation Blocks and the Pipe Network use that Function to determine connections to adjacent Blocks, this would reduce a ton of Server load.
Profiling indicates that we are fine on memory and really cpu constraint, so I am all in favor of trying to trade memory for cpu Is this solution implemented in the latest GT ?