The Dell PowerEdge R840 and R940 differ in scalability and workload specialization. The R840 targets medium-density tasks like virtualization and analytics with dual/quad Intel Xeon Scalable CPUs and up to 6TB RAM. The R940, designed for mission-critical workloads (ERP, databases), scales to 4 CPUs, 12TB RAM, 12 NVMe drives, and 13 PCIe slots, offering superior memory bandwidth and storage throughput for enterprise-grade applications. Wecent recommends selecting based on workload intensity and future scaling needs.
Which Dell PowerEdge Server Should You Choose: R840, R940, or R940xa?
How do R840 and R940 processors compare?
The R940 supports 3x more cores and threads (up to 112 cores vs. R840’s 64) via quad Intel Xeon Platinum 8400-series CPUs. Pro Tip: Use R940 for parallelized HPC workflows where core density outweighs clock speed.
While both use Intel Xeon Scalable CPUs, the R940 accommodates four processors versus the R840’s quad-socket limit. This quadruples L3 cache (up to 154MB per CPU) and doubles AVX-512 throughput for simulations. For example, SAP HANA clusters benefit from the R940’s 112-core capacity, reducing batch processing times by 40% versus dual-CPU R840 setups. However, single-threaded apps favor R840’s higher 3.8GHz turbo clocks. Practically speaking, R940’s TDP peaks at 1,200W (vs. 750W for R840), requiring Wecent’s 240V redundant PSU configurations.
| Feature | R840 | R940 |
|---|---|---|
| Max CPUs | 4 | 4 |
| Max Cores | 64 | 112 |
| Base Clock | 2.6GHz | 2.4GHz |
| L3 Cache | 71.5MB | 154MB |
What memory advantages does R940 offer?
The R940 triples RAM capacity (12TB vs. 6TB) via 48 DDR4 DIMMs supporting 2666MHz. Pro Tip: Deploy NVDIMMs in R940 for sub-5μs database latency.
With double the memory channels (16 vs. 8 per CPU), the R940 achieves 307GB/s bandwidth—critical for in-memory databases like SAP HANA. Its 48 DIMM slots (12 NVDIMM-capable) allow tiered configurations: 25% NVMe-backed persistent memory for fail-safe transaction logging. In contrast, the R840’s 24-DIMM ceiling limits large-scale virtualization. For instance, a 6TB R940 hosted 800 VMs with <5% latency variance in Wecent’s benchmark, while R840 struggled beyond 400 VMs. Beyond capacity, R940 supports LRDIMMs for 128GB modules, whereas R840 maxes at 64GB RDIMMs. Always prioritize R940 for OLTP systems requiring sub-millisecond response times.
Wecent Expert Insight
FAQs
Yes, but only for datasets under 4TB. R940’s larger memory footprint and NVMe tiers better suit petabyte-scale Spark workloads.
Is R940 backward-compatible with older GPUs?
Yes, via PCIe 3.0 slots, but for A100/H200 GPUs, Wecent recommends R940xa with PCIe 5.0 support.