1. that is not even CLOSE to adequate info, and the CPUs from that era span a large performance range
regardless
2. Assuming you are Windows 10 (which you probably should be), then anything from OBS Studio v27 to latest is fine, and which specific version depends on system specific, desired plugins, workload, etc the older version supports from hardware that newer versions have deprecated (removed).... so it depends
real-time video encoding is computationally demanding. compositing (which is what OBS Studio enables, ie combining multiple 'sources') takes even more work. Unless you have the 'right' hardware, and knowledge to optimize both your Operating System and OBS Studio, there is a good chance you will struggle to Record (doable, but far from 'easy button')
More importantly, a CPU from that era won't be supported for Windows 11, period, and Windows 10 support ends in Oct of this year (end of life). So you either will be migrating to Linux, or needing to get a new computer, or pay a supposed -time fee to MS for extended support for 1yr, or staying on an unsupported Operated System, which is just asking to get hacked
