How to Upgrade a Prebuilt PC

A prebuilt can usually take more memory and storage with no fuss. Whether it can take a bigger graphics card or a new power supply depends on how much of the machine is standard, and some brands make that hard to find out. Identify what you have before you buy anything. With memory and SSD prices where they are, a prebuilt may well have been the cheapest way to get these parts, as our prebuilt versus custom comparison explains, so you want your upgrade money to land on parts that actually fit.

Find out exactly what you have

1. Find the exact model. Look for the sticker on the case or the box, then pull up the service manual or spec page on the maker's support site. It often lists the slots, the power supply and what's supported.
2. Read the hardware in software. HWiNFO, or System Information in Windows, will give you the CPU, memory configuration and board name, if the maker reports one.
3. Open the side panel and take photos. Note the label on the power supply, how many memory slots there are and how many are filled, any free M.2 slots and the space around the graphics card.

Spec sheets vary a lot in how much they tell you. Dell lists the Tower Plus (EBT2250) with two memory slots, both filled on the base configuration, a 460 W power supply and three PCIe slots. Lenovo says the Legion Tower 5i Gen 10 uses a customized B860 micro-ATX board. Dell's Alienware Aurora spec sheet gives no motherboard model at all. NZXT's Player systems use standard parts, which is much simpler to plan around.

Signs a part is proprietary

Don't assume a retail power supply will connect just because the wattage looks right. Dell describes the Tower Plus's unit as a 460 W, 12 V supply, which is a good reason to check what connectors you're dealing with first.

Warning: Never connect a power supply to a board unless you've confirmed both use the same standard. Non-standard pinouts can look almost right and still destroy the board.

What's usually safe to swap

1. SSD. Add a drive to a free M.2 slot, or replace the existing one. Follow our M.2 install guide, and check the manual, because some compact prebuilts have only one usable slot.
2. Memory. Most desktops use standard DIMMs. Many prebuilts fill every slot with small sticks, so you may be replacing a pair and not adding to it. Match the DDR generation and the maker's listed maximum. Our RAM guide explains how much is worth buying, and current kits are listed here.
3. Graphics card. Check three things before you buy: the power supply's wattage against the card maker's recommendation, the connectors the card needs, and the card's length and thickness against the case. Our graphics card guide covers the rest. Entry systems often have very little headroom: Alienware's Aurora base configuration uses a 500 W unit, for example.
4. Case fans and cooler. Most case fans are standard sizes. A CPU cooler is fine to replace if the mount is socket-standard, not a custom bracket.

Before you touch anything, shut the PC down, switch off and unplug the power supply, and touch bare metal on the case to discharge static.

What usually isn't worth changing

• The motherboard. Custom boards often won't fit a retail case layout, and retail boards may not fit the case or front-panel connectors you already have. Microsoft also says that replacing the motherboard means Windows will no longer find a matching license, so you'll have to reactivate.
• The CPU. Stick to chips listed on the BIOS support page for that exact model, and check that the existing cooler can handle a hotter part.
• A proprietary power supply. If you need more power and the unit isn't standard, buy only the maker's approved replacement, or accept that this is where the machine's limit is.

Once you need all three, you may be better off starting over. A new custom build or another prebuilt can make more sense than rebuilding one piece at a time.

Warranty considerations

Read the warranty document before you open the case. Look for which parts the maker considers customer-replaceable, and whether upgrades need to be done by an authorized service provider.

In the US, the Federal Trade Commission's guide to the Magnuson-Moss Warranty Act says tie-in sales provisions, which state or imply you must use an item or service from a particular company to keep your coverage, are generally not allowed. That doesn't stop a maker from refusing to repair damage your upgrade caused. If you install a part badly and it kills the board, that repair can legitimately be on you. Warranty rules differ elsewhere, so check your local consumer law.

Protect yourself in practical ways:

• Keep every original part and its packaging.
• Photograph the inside of the PC before you change anything.
• Put the original parts back before sending the machine in for service.
• Keep the receipts for what you added, because those parts carry their own warranties.

A sensible upgrade order

1. Memory, if you're running out in the apps you use.
2. Storage, when you're short on space or still booting from a slow drive.
3. Graphics card, after confirming power and clearance.
4. Monitor, which may give you more than any part inside the PC. We argue that case in why the best upgrade is usually your monitor.

Before you spend, run your exact model and intended parts past Socket, our build assistant, to catch a clearance or power problem early.