A Dell BIOS update can change which memory a PowerEdge server or Precision workstation runs correctly. The BIOS carries the Memory Reference Code that trains every module at startup, and Dell's release notes regularly add support for new DIMM types, configurations and processors. So the safest memory upgrade on a Dell starts with the firmware: check the BIOS version, read the memory items in the release notes, update, then install.
What Dell BIOS updates change for memory
| Release | Memory item in the notes |
|---|---|
| PowerEdge R630XL / R730XL BIOS 2.5.5 | Added support for mixed quad-rank and dual-rank LRDIMMs; updated Memory Reference Code |
| PowerEdge R740 / R640 BIOS 2.2.10 | Updated Processor and Memory Reference Code for 2nd Gen Xeon Scalable |
| 14th generation recommended BIOS | Memory Reference Code updated |
The pattern holds across generations: new processors bring new memory speeds, and memory fixes arrive through the BIOS. A server running a BIOS from before a module type was supported may not train it correctly.
The rules firmware cannot change
Some limits come from the platform, not the firmware. Dell's manuals list them by model:
- No RDIMM and LRDIMM mix. Dell's R740 manual says they must not be mixed.
- Matching capacities on 16th generation servers. The R760xs manual states that mixing different DIMM capacities is not supported.
- Mixed speeds run at the slowest. Install matched modules to avoid the drop.
- Matched does not mean Dell-branded. Dell defines equal DIMMs by electrical specification and capacity, and notes they may be from different vendors.
Dell warns that an invalid configuration might not boot, might stop responding during memory configuration, or might run with reduced memory.
Pre-upgrade checklist for Dell
- Find the BIOS version: press F2 at boot and open System BIOS, System Information, or check iDRAC.
- Open Dell Support, enter the Service Tag and read the latest BIOS release notes for memory items.
- Update iDRAC, then the BIOS, each as its own job.
- Plan the population from the model's manual: socket order, matched capacities, one module type.
- Install, let the first boot run full memory training, then confirm the total in F2 or iDRAC.
The update steps are in how to update BIOS on Dell PowerEdge servers, the install in how to install RAM in a Dell PowerEdge server, and the per-model rules in the Dell PowerEdge memory upgrade guide.
Dell memory from NEMIX RAM
NEMIX RAM lists memory by Dell model, including the R740, R750, R760 and Precision 7960. Browse Dell PowerEdge server memory, DDR4 RDIMM and our Dell memory page.
Frequently asked questions
Can a Dell BIOS update change which RAM works?
Yes. Dell BIOS updates carry the Memory Reference Code that trains memory, and release notes add support for new DIMM configurations. The R630XL and R730XL BIOS 2.5.5, for example, added support for mixed quad-rank and dual-rank LRDIMMs.
Do I have to use Dell-branded memory in a PowerEdge?
No. Dell's PowerEdge R760xs manual describes equal DIMMs as modules with the same electrical specification and capacity, which may be from different vendors.
Should I update the BIOS before or after adding memory?
Before, with the existing memory installed. The new modules then train under the latest memory code.
What does Dell say happens with an invalid memory configuration?
Dell's manuals warn the system might not boot, might stop responding during memory configuration, or might run with reduced memory.
Which order should I update Dell firmware in?
Dell recommends iDRAC first, then BIOS, then CPLD or FPGA, then the rest. See how to update BIOS on Dell PowerEdge servers.
Buying for more than one system
IT teams and integrators that maintain Dell PowerEdge fleets can standardize on one kit per model. Request a quote with your models and quantities, or send us your system model and we will confirm the right module before you order.
Steps and rules are summarized from the vendors' published documentation; follow the guide for your exact model.