I found where is a problem. One my instance is running with broker arbitrage. If I start any second instance, whitch trying use the same DLL, is a verry slow.
In the manual:
Brokers A and B must not use the same broker plugin Dll.

But if use other instance, must be also other Dll.

Instance 1 (ARB).... Broker A ... plugin1.dll, Broker B ... plugin2.dll
Instance 2 - only one plugin - Broker C ... plugin3.dll <-- don't use the same dll like Instance 1
Instance 3 - only one plugin - Broker C ... plugin3.dll

Sorry for my english.