HP DL380p G8: Maximum RAM Speed with 24x 32GB LRDIMMs

Hello all, 

I some questions regarding our two HP DL380p G8 server: 

1. Server 1 has 24x 32GB LRDIMMs (14900) with 2x Intel Xeon E5-2680V2
2. Server 2 has 24x 16GB RDIMMs (14900) with 2x Intel Xeon E5-2643V2

Currently server 1 is running with 1067 MHz clockspeed for RAM. I have checked the HPE online tool for RAM configuration. The tool says with our configuration we should be able to run with 1333 MHz instead of 1067 MHz. I´m not sure if this is correct or not?! Maybee anyone can answer us the qestion. 

My second question, is there a quite difference on performance betweeen the 1067 and 1333 MHz. We run a view Terminal Servers based on Windows on the server. 

On server 2 it is the same, the RAM speed is lower as the possible maximum supported by CPU and RAM. But I think this is normal when you use all 24 DIMMs, but on server 1 it is 800 MHz less what the memory can run. 

Thanks in advanced