Anyway, I don't see why you wouldn't be able to play. It's not like there is anything bad besides the auto-un-balance.
I have a Pentium G860 clocked at 3 GHz, which should be enough (like it is for every other game I've played, even ones newer than TF2). Unfortunately, TF2's optimization is so poor that I receive terrible fps drops all the time. It drives me mad.
Oh yes, now I understand you. I did get the drops too, and I used a high-fps config so it doesn't affect me that much now. I think the outdated Source is the problem here?
I hope the game gets ported to Source 2. Maybe someday Valve will realize what trouble people go through to run it...
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<a href='https://www.reddit.com/r/tf2/comments/3gm3w3/performance_open_letter_to_valve_employees/' class='bbc_url' title='External link' rel='nofollow external'>Source</a>