Time Compression (TC) is very, very computer dependent. But the relative "strength" of the computer isn't as important as its configuration. The more that runs in the background on a computer while playing an SH game, the more issues that will be encountered. Member Front Runner a while back was running into issues with his install of FotRSU. If you really want to get bored to tears (unless you find the details and findings as we went interesting, of course), refer to "
Base Time 2018".
Suffice to say, the game is an old DirectX v9.0c game, and a lot of its internal code uses dll library files in DirectX v9.0c for its "timing". The old "target", if you will, was a display that showed 30 frames per second, based upon the display card's "clock". Newer vid cards run much faster than the old cards of even just a few years ago, and that "clock" does matter to the game. Further complicating things is the temporary buffer "streams" used by the game for video, audio, and memory management (among other resources, I'm sure). The 'modern' OS uses "virtual space" much more than XP did, which is what SH4 was written to, and things can get mixed-up there, which is why it is recommended to not swap out to Windows while playing the game.
Then just the math of TC comes into play, as you suggest, with the "contacts". I have seen instances where the submarine had traveled completely beyond the contact, suffered damage from the enemy, and is then in a sad state. We used to have the game capped at 2048x TC, and still recommend a player use no more than 1024x, but have since raised the max to 4096. All of those "streams" used by the game can and do get out of "sync" with each other, and most times after the use of high TC (which "high" is relative for the computer), you will lose audio that doesn't restore until after a Save, Exit, restart & Load, and all sorts of graphics anomalies might be encountered. Even the AI response can be thrown out of whack. Again, computer dependent. If you want to raise it to 8192, you edit the "Main.cfg" in the Data / Cfg folder of the game, prior to starting a career. If you are already playing, you would have to find all of the instances of "[Time Compression]" in the Save folders, which are usually in "C:\Users \UserName \Documents \SH4", unless you've used MultiSH4, and then it would be whichever folder you used there.