The trick is to find the bottleneck. The usual suspects are the CPU and the MoBo bus speed. Speaking of bus speed, as an analogy, say you have a very nice Ferrari but you have to drive it on a narrow bike path, can't get much speed there... Same applies to Hard Drives and and anything else connected to the Mobo and using it's resources. That is why sometimes you come across someone with a lower end rig but it's performances leave you in the dust... You also have to look at what software you have installed. Some anti-viruses are notorious for slowing down your rig and hogging resources. As a side note, the one I use for editing is not connected to the internet, has no anti-virus, games, etc. It's dedicated to editing and compositing. Building a rig sometimes feels like alchemy...
PC Win 10 Pro 64-bit 16gb
Ryzen 9 3900X 12 Core 4.60GHz
Radeon RX 5700 XT
Cameras: Canon XF305 + Canon XH-A1 and a bunch of others
Vegas Pro 16, User since Vegas 3.0
Your rig is fairly decent if you were still editing SD or 1080 files back in 2011 using Vegas 11. Adding RAM may help. You don't mention if you are using an SSD, or what source of video you are editing. H264 and H265 can slow down Vegas, particularly in a multicam edit, on older rigs.
You might want to consider a whole system replacement, but if that is not an option, replacing your mechanical with an SSD breathes new life into an aging system.
Your O/S is most likely Windows 7 which is no longer supported or getting security updates.
I replaced my 2009 vintage i7 laptop in Jan 2020 with a Lenovo IdeaPad S145 and what a difference it has made. Reinstalling software was a pain but a worthwhile one ☺
If you are getting a laptop, note that not all models have the same specs! Check the specs! For the 'saving' of $100 you often get short changed with a smaller or lower res screen, slower CPU or lower capacity SSD. My Lenovo was a classic case and luckily I noticed the subtle differences.
My system specs: Intel i7 7700k 4.20 GHz, GTX1060, 16GB RAM, Gigabye Z170 HD3, Vegas Pro 13 (x64), Windows 10 x64 Pro, Vegas Production Assistant 1.0, VASST Ultimate S Pro 4.1, VASST Infiniticam 1.7, Neat Video Pro 2.6