Sorry it took me so long to respond, but I really your responses. I tried using the timebar command line but every version of SCP would either give me page fault error or it would say that command line do not exist. So instead I took six screenshots to show what is happening. The first three are of the 3.5.5 version and second three are of the open_t version with HTL on.






As you can see the HTL version is faster but both versions slow way down when an ani is started such as when a new ship warps in. Also there are frequent pauses as well.
I also ran the original exe and your 3.3 version both seem to run faster than the newer versions but I don’t know the command line to show the fps for these versions.
I forgot to mention that I’m using 45.23 nvidia divers with Antialiasing and Anisotropic Filtering turn off.
I hope this helps.
Oh, like to add that even though my processor is really old I've been able to install Homeworld 2 on this computer and it runs

smoother than SCP even though it has a similar framerate.