What should I check before buying used 64GB DDR4 RAM?

Start with the exact model number printed on the labels. Check that Corsair identifies it as desktop DDR4, and confirm the capacity, speed, and whether it is ECC or registered server memory. Those types are not interchangeable with ordinary desktop RAM, and a photo or listing title alone may not tell the whole story.

Also check how many modules make up the 64GB. If possible, ask the seller to show the full capacity detected in BIOS on a compatible machine. That does not prove every stick is healthy, but it can catch a mislabeled or incomplete kit.

The bigger concern is not whether it looks clean, it is whether it passes a proper memory test. If you can test it before buying, bring a compatible system and run a bootable memory tester. A quick check is only a screen, not a guarantee. If you buy it, test the full kit for several passes before trusting it with important files or work.

Intermittent memory errors can cause confusing crashes or data problems, so I would not treat a successful boot as proof that it is fine.

$100 is low, but a low price by itself does not establish that anything is wrong. DDR4 prices and local listings vary, and some sellers just want older parts gone. Compare the exact kit against current local prices rather than judging from the capacity alone.

For a private sale, keep the deal simple: inspect the labels, check that the sticks are not visibly damaged, and avoid paying before you have a reasonable way to confirm what is being sold.

Check that the kit suits your motherboard and CPU, especially the memory type and configuration. Also ask whether the modules were sold as one matched kit or assembled from separate sticks. Mixed modules can work, but advertised speed may require manual adjustment, and stability can depend on the system.

If you cannot test them in your own setup, at least get clear photos of every label and the exact part number before making the trip.