Hello,
I am using HEM2 every day on various sites without any performance issues whatsoever. My problem always begins when I play MTT's on sundays. Basically I have shut all other sites down, and made sure that I'm not running any processes that hogs up alot of memory. I can see though, that HEM2 uses alot of memory which causes PokerStars client to respond really slowly. If I close down HEM2 everything runs smoothly again.
My computer:
i7-4790K CPU @ 4.00 Ghz
NVIDIA GeForce GTX 760
Samsung SSD 840 EVO 500 GB
16 GB RAM
Windows 7 Ultimate 64-bit