Mixing 32GB and 64GB DDR4 DIMMs on Dell PowerEdge R750xs – Compatibility and Performance Impact

Hello Dell Community,

We’re currently running a Dell PowerEdge R750xs (3.5") server used to host DHIS2 and supporting services in LXC containers.

Current configuration:

• Model: Dell PowerEdge R750xs (3.5")
• CPU: 2 × Intel Xeon Silver 4310 (12 cores each, 24 total / 48 threads with HT)
• Memory: 128 GB DDR4 @ 3200 MT/s (4 × 32 GB DIMMs)

We recently purchased an additional 256 GB of RAM (4 × 64 GB DIMMs) to increase performance and overall capacity to 384 GB total.

Before installing, we’d like to confirm:

1. Can we safely mix 32 GB and 64 GB DDR4 DIMMs on the same R750xs server?
2. Will mixing different capacities affect performance?
3. Are there any Dell-recommended slot population orders when mixing DIMM sizes?

We haven’t installed the new modules yet — just want to be sure it’s fully supported and optimal before proceeding.

Thanks in advance for your guidance!