Intel core Ultra 9 285k Limits of the RAM Spec

[Napoleon]

Hello, I just bougth my 285k processor and i want to know what are the limits of the RAM that the processor can support. (I don't think i will ever need the 192GB of RAM but i still want to ask this).

The spec says that it can go up to 192GB with a speed of 6400MHz.

So theorically you can get 4x48GB RAM sticks that has a speed of 6400MHz and it should work perfectly rigth?

Or do you need to lower the RAM speed to use all 4 RAM slots because of inestability issues?

And finally, what is the case if using UDIMMs or CUDIMMs? does that make the spec change?

[pressed_for_time · Accepted solution]

Yes, 6400 is the maximum memory speed unless XMP is activated at least as long as no more than two sockets are used.

Once XMP is activated it's really a question of what memory speeds the motherboard concerned supports. Z890 boards for example generally support up to 9000. Speeds much over 8000 seem to need CUDIMMs - these are UDIMMs fitted with a clock driver.

Motherboard manufacturers publish lists of supported memory modules. The screenshot below is an extract from the list of 8400 speed modules for an ASUS Z890 motherboard

As you can see these all support no more than 2 sockets. Using all 4 sockets is not entirely straightforward. ASUS have a BIOS update that enables four socket support for a particular type of 6400 memory (see graphic below). ASUS is also saying that the board will support 256GB maximum. It seems that otherwise 5600 is the maximum speed. So if you plan to use all four sockets it would be advisable to consult the board manufacturer about what speeds can be achieved in practice.