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ASRock X299 MB - Can I only use 2 of the avail 8 DIMM slots

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New Member
Nov 29, 2020
First time poster...

I have an ASRock X299 Steel Legend MB that has 8 DIMM slots. I'm using an I9-7920X.

I have ordered a Crucial DDR4 2x32 GB - 3200 kit (CMW64GX4M2E3200C16).

When I look at the MB manual it only shows 4 and 8 DIMM configs.

When I go on ASRock's website, it shows this kit as supporting 2 DIMM slots (https://www.asrock.com/mb/Intel/X299 Steel Legend/index.us.asp#Memory).

My question is whether I can use just 2 of the 8 DIMM slots or I have to use a minimum of 4 slots.
You can use two slots. It will mean you are only running in dual channel mode and are leaving performance on the table. I would recommend return the 2x32gb and going 4x16gb route for better performance.
2 should work. You're just losing half the possible ram bandwidth if you do so though. Ideally should have got 4x16 for same total capacity.
Thanks to bmwbaxter and mackerel for your quick responses. Very much appreciated.
As was said earlier, you can use that kit, but your system is quad-channel so you're losing some bandwidth. Will it be noticeable? That depends on what you do with that system. If it's simply gaming for the most part, then you're going to be ok. Just be sure to check your manual as to which slots to put the two sticks in. Ideally, you'd have a 4x16GB kit.

Can you actually use more than 32GB in the first place?
Yes, I'll be using KVM with GPU passthrough for a Windows VM and I will be doing programming/ML with the box. Per everyone's suggestions, I ordered a second 2x32 kit from the same vendor, so I will be able to take advantage of the quad-channel capabilities. Thanks again for everyone's insights and very quick replies.
The same exact kit, yes? If so, you should be set. You may need to tweak some voltages to get it all to work, but we'll cross that bridge when we get there. ;)