i recently stumbled upon the fact that it is possible to use a desktop graphics card in tandem with your laptop. with my aging laptop i naturally turned to this option because i don't currently have the money to buy a whole new laptop. i know i will need to purchase some hardware if indeed i can use this setup on my laptop.
i took these pictures and screenshots to try to help with the process of helping me. (sorry for it being on mediafire. imgur was down)
It's possible, but it's not really a budget option, and highly, highly niche. You'll need some crazy adapter, and most practical solution would be Thunderbolt, since Thunderbolt is basically 4 lanes of PCI-e over a display port connection, but I highly doubt you have Thunderbolt. USB is too slow, and too much lag, not to mention it will eat up additional CPU cycles. And most other interfaces are out-dates, such as express cards, but then, assuming such an adapter does exist, comes a power requirement issue, as PCI-e is spec'd to supply 75w, and that's more than a good chunk of laptops can provide at full load, with a huge number of them designed to use less than 65w total. It's possible to go the express card route, since it does carry 1 lane of PCI-e, but you will need an adapter (you're looking at $70 - $100 for said adapter), a power supply ($40 or so), and, of course, a GPU ($150 or so). If you don't have express card, it's possible to use mPCI-e, which you do have for sure (occupied by your WiFi card), but it has to be wired properly; apparently some mPCI-e only use USB wires instead of PCI-e ones (such as ones specifically designed for WiFi), and if you have the latter, you're SoL.
You'd be better off getting a new laptop, as this process will take time, research, money, and some headache to get it set up, assuming you're laptop is even compatible with said set up in the first place. And even then, how long you get to enjoy the fruits of the labor depends on how well your laptop has aged.
If you're hell-bent on this, this is a good starting resource: