How to buy RAM without overpaying
Memory is one of the few parts of a PC where the cheapest sensible option and the most expensive one feel almost the same in daily use. That makes it a good place to save money, and an easy place to waste it. This guide walks through the choices in the order you should make them: how much you need, which generation your board takes, what speed is worth paying for, and when to buy.
1. Start with how much you need
Capacity matters more than anything else on the box. When a program runs out of memory, the system starts moving data to the SSD, and everything slows down far more than any speed difference between two kits could make up for. So settle the size first, then spend what is left on speed.
- 16 GB is enough for web browsing, office work and most games on their own. It starts to feel tight if you keep a browser with many tabs, a chat app and a game open together.
- 32 GB is the comfortable choice for a gaming or general-purpose PC today. It leaves room for background apps and for games that keep growing.
- 64 GB or more is for video editing, large photo libraries, virtual machines, big code builds or running local AI models. If you don't do one of those, you probably won't notice it.
Buy memory as a matched kit of two sticks rather than one large stick. Two sticks run in dual channel, which roughly doubles the bandwidth on most desktop boards. Four sticks look nice but are harder for the memory controller to drive at high speeds, especially with DDR5, so two larger sticks are usually the better buy.
2. Check which generation your board takes
DDR4 and DDR5 are not interchangeable. The notch sits in a different place, so a stick of one will not fit a slot made for the other. Your motherboard decides this for you, so look up its model before you shop.
Recent AMD desktop platforms take only DDR5. Intel boards from the last few generations come in both DDR4 and DDR5 versions, sometimes with almost the same name, so check the exact model. Laptops mostly use soldered memory or SO-DIMM sticks, which are smaller and not the same as desktop sticks.
If you are upgrading an older DDR4 system, there is no need to change platform just for faster memory. A good DDR4 kit is still fine for most uses, and it is often cheaper per gigabyte.
3. Speed and timings, in plain words
Two numbers describe how fast a kit is. The first is the transfer rate, such as 6000 for DDR5-6000. Higher means more data per second. The second is the CAS latency, written CL30 or CL36, which counts how many clock cycles the memory waits before it answers. Lower means a shorter wait.
The two work together. A kit with a higher rate can afford a higher CL number and still answer just as quickly in real time. A rough rule is to divide the CL number by the rate and multiply by 2,000 to get the wait in nanoseconds. DDR5-6000 CL30 works out at about 10 ns, as does DDR4-3200 CL16.
For most desktop builds the sweet spot sits in the middle of the range. Very fast kits cost a lot more and often need careful tuning to be stable. Very slow kits save little. Check your board's support list (often called the QVL) and the processor maker's guidance for the speed the platform handles comfortably.
One more thing: memory runs at a slow, safe speed until you switch on its profile in the BIOS. It is called XMP on Intel and EXPO on AMD. Many people pay for a fast kit and never turn this on, so it's worth the two-minute check after you build.
4. Things that don't matter much
- Heat spreaders and lights. Desktop memory runs cool at normal settings. Tall heat spreaders can get in the way of a big CPU cooler, so check the height if your case is tight.
- Brand of the stick. A small number of factories make the memory chips. Different brands often use the same chips, so compare the speed, timings and warranty rather than the logo.
- Single-sided or dual-sided. This makes a small difference that only matters if you tune memory by hand.
5. When to buy
Memory prices move in long cycles. When factories make more than the market needs, prices fall for months. When they cut back, or when demand jumps from data centres, prices climb quickly. Day-to-day changes in a shop are mostly noise around that trend.
That makes it worth looking at the price per gigabyte over a few weeks rather than at one day's discount. If the cost per gigabyte for the kit you want has been falling steadily, waiting a little can pay off. If it has started climbing across several shops at once, it is usually better to buy now rather than hope for a dip.
Sales events often bring real cuts on popular kits, but the "was" price shown is not always one the kit actually sold at. Comparing against a few weeks of history is the simplest way to tell a real deal from a relabelled one.
6. A short checklist before you pay
- The generation matches your board: DDR4 or DDR5, desktop or laptop.
- It is a kit of two sticks with the total you want.
- The speed is one your platform supports well.
- It is low enough to clear your cooler.
- The shop's price per gigabyte is in line with the rest of the market today.
Once it is in, switch on XMP or EXPO, then run a memory test overnight if you can. A kit that passes a long test once rarely causes trouble later.
7. Where to go next
Our price list shows today's cheapest kits by price per gigabyte, with every shop linked. If you are waiting for a price to fall, you can set an alert on a kit and get one email when it drops below your target.