That's may correct. What matters is single thread performance.
Take a look here: https://www.cpubenchmark.net/singleThread.html
It gives you a overview about single thread performance.
Your CPU i3-3120M has a score of 1285. Btw: Its a Sockel G2 and easy to upgrade. A 4th gen i7 QM for just 25$ would be a great performance boost.
The Xeon X5670 in my build- released in 2010 ) has a score of 1345 that's not much more than yours and APB is working perfect on it.
Link to my cheap build: https://valid.x86.fr/h9dzt3
Whatever throttles your performance. Its not the APB engine.
Maybe its your outdated windows, GPU drivers, other drivers or installed bloatware/adware. Maybe even a mix of everything, but its not the APB engine.
@Mitne I wonder how bad your computer must be... that you're unable to play a 10 year old game on decent framerate. Or does your pc just overheat?
I got my a RX 580 GPU downclocked to 650Mhz. 4 FullHD screens connected to it while multitasking with several applications and playing apb on ultra settings...
Still getting more than 80fps in APB stable. CPU usage is around 10% ~ The whole system is not very expensive might cost 500€.
You really think APB could become a enemy for GTA V ? )) Okay they can just handle 32 players due crappy P2P network, but also have many other features to offer.