Humm, well I have the steam version too and have had no issues what so ever....
I have modded my SH5 to the hilt and still no errors....I do remember a time though when I first bought SH4 and it used to crash to the DT all the time I believe the issue was the Graphics card...But that's just my two cents worth...
Happy hunting and I hope you sort it out soon..
Regards Nuke...