I have traded with IC Markets for 4 years now and 2 other brokers for 12 years and can honestly claim that platform freezes are common. They are the result of 3 reasons:
1. Multiple / combinations of symbols, charts and their indicators and/or EA’s
2. Slow/Low quality computer operating system
3. Internet connection Ping higher than 10ms and download speed lower than 50mbps.
I have one powerful laptop dedicated to news trading with only 1 naked MT4 chart (no indicators or ea’s) only with the 1 symbol that I am trading on news announcements. I never have freezes/disconnections on that computer whereas my other “loaded” computers do indeed freeze.