Can you upgrade a pre-built PC?

You can upgrade some pre-built PCs

If you've purchased a pre-built PC with a standard chassis and motherboard, there's a very high chance you can upgrade various parts. If either or both are proprietary, your upgrades may be limited to just RAM, GPU, and storage. It's not something that's easily considered when buying a PC online since not all vendors will provide details or internal photos.

Really, for gaming PCs, the major component to upgrade would be the graphics card. Replacing the card that comes preinstalled is a sure way to improve in-game performance. We always recommend spending as much as possible on the best graphics card you can afford.

It's actually in the system integrator's best interest in making a profit to have you pay for the upgrades outright. The companies want you to spend the money with them and not have you buy an aftermarket component and save money. This is why you may find some proprietary components or a case that specifically caters to OEM parts.

The easiest way to buy a pre-built PC that can be upgraded later is to buy one that uses an ATX standard motherboard and PC. If the PSU (power delivery) and motherboard (compatibility) are able to handle various upgrades to the system, you shouldn't have any issues. But then, really, you should be building the PC from scratch — and we have a guide on how to build a PC.

Watch out for system warranties

When purchasing a pre-built system, if you have a warranty (or add in the extended warranty), it's important to be careful when upgrading or replacing hardware. Such moves could invalidate the coverage, leaving you all out of luck if the PC runs into complications and the vendor refuses to support it due to you making internal changes.