DDR4 RAM Size

I’ve been looking at computer hardware on AliExpress a lot recently and I saw an advert for a motherboard which can take 256G DDR4 RDIMMs (presumably LRDIMMs). Most web pages about DDR4 state that 128G is the largest possible. The Wikipedia page for DDR4 doesn’t state that 128G is the maximum but does have 128G as the largest size mentioned on the page.

Recently I’ve been buying 32G DDR4 RDIMMs for between $25 and $30 each. A friend can get me 64G modules for about $70 at the lowest price. If I hadn’t already bought a heap of 32G modules I’d buy some 64G modules right now at that price as it’s worth paying 40% extra to allow better options for future expansion.

Apparently the going rate for 128G modules is $300 each which is within the range for a hobbyist who has a real need for RAM. 256G modules are around $1200 each which is starting to get a big expensive. But at that price I could buy 2TB of RAM for $9600 and the computer containing it still wouldn’t be the most expensive computer I’ve bought – the laptop that cost $5800 in 1998 takes that honour when inflation is taken into account.

DDR5 RDIMMs are currently around $10/GB compared to DDR4 for $1/GB for 32G modules and DDR3 for $0.50/GB. DDR6 is supposed to be released late this year or early next year so hopefully enterprise grade systems with DDR5 RAM and DDR5 RDIMMs will be getting cheaper on ebay by the end of next year.