What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
It can be a good ZFS SLOG for a workload bottlenecked by synchronous-write latency, but it is not a general-purpose ZFS speed upgrade. Radian designed the RMS-200 as a low-latency NVMe log device with onboard power-loss protection. It is now end of life, so a buyer also has to verify the exact card, its condition, and compatibility with the server.
When does a ZFS SLOG help?
A separate intent log, or SLOG, gives ZFS a dedicated device for logging synchronous writes. ZFS already has an intent log; a SLOG moves that log to a separate device. It does not turn asynchronous writes into a faster general-purpose write stream.
OpenZFS puts the key limitation plainly: “If your workload has no synchronous writes, a SLOG changes nothing.” (OpenZFS: Caching and Auxiliary Devices) Workloads that may benefit include NFS servers and databases when their synchronous writes are held back by commit latency. The client’s durability behavior and the pool’s existing latency also matter.
A SLOG is therefore worth considering when measurements show that synchronous-write latency is a real bottleneck. It is not a reliable upgrade based only on a drive’s interface or headline throughput. Compare the same workload before and after the change.
Recommended Free Tools
#1 Best Overall
- 1.92TB SATA 6Gb/s 2.5-Inch Read-Intensive Enterprise SSD — Intel D3-S4510 series enterprise solid state drive designed for read-intensive workloads including virtualization, cloud applications, databases, content delivery, and large-scale analytics environments
- 64-Layer Intel 3D TLC NAND — Read Intensive Endurance — 1 DWPD read-intensive endurance rating delivering 560 MB/s sequential read and 510 MB/s sequential write speeds with 97,000 random read IOPS for consistent low-latency data access
- Enterprise Data Protection — AES 256-bit encryption, Power Loss Protection, and End-to-End Data Protection ensure data integrity and compliance in always-on 24/7 data center environments
- Drop-In SATA Compatible — Compatible with existing SATA infrastructure across Dell PowerEdge, HPE ProLiant, Supermicro, and other enterprise server platforms — no additional hardware required. Innovative firmware updates complete without server reset to minimize downtime
- 2 Million Hour MTBF Enterprise Reliability — Rated for continuous 24/7 operation for mission-critical storage deployments requiring maximum uptime and reliability
What the RMS-200 offers
Radian describes the RMS-200 as an NVMe PCIe x8 Gen3 NVRAM accelerator intended for low-latency logging. Its product page says it supports NVMe block transfers and memory-mapped PIO, and describes onboard ultracapacitors and firmware that transfers data from volatile DRAM to persistent NAND during power loss. (Radian RMS-200 product page; RMS-200 datasheet)
That is the manufacturer’s description of its protection mechanism, not independent confirmation of a particular card’s operation. It does not establish that a used unit’s capacitors, firmware, or NAND are healthy, or that the card will work in every motherboard, BIOS, operating system, or ZFS platform.
Radian’s undated product page, checked in 2026, claims over 1.3 million IOPS for 4K random writes and over 5.5GB/s for 128K random writes. These are vendor-published figures; the page does not provide independent replication or a ZFS workload benchmark. They should not be treated as evidence of the performance a particular pool will achieve.
Rank #2
- 3.84TB enterprise SATA solid state drive in a 2.5-inch form factor — ideal for read-intensive server and data center workloads including virtualization, content delivery, and database read replicas
- SATA 6Gb/s interface with sequential read speeds up to 555 MB/s and sequential write speeds up to 530 MB/s for consistent, high-throughput data access
- 3D TLC NAND flash with 1 Drive Write Per Day (DWPD) endurance rating and 7,008 TBW total write endurance over a standard 5-year period
- 96,000 random read IOPS and 35,000 random write IOPS with enterprise-grade power loss protection and error correcting code for data integrity in mission-critical environments
- Dual Dell/SK Hynix label (Dell DPN 03GDK0) — fully compatible with any system supporting a standard SATA interface, not limited to Dell systems; 2,000,000-hour MTBF reliability rating
Which RMS-200 capacity is it?
Radian’s product page and datasheet describe different capacity configurations. Identify the exact SKU and revision rather than assuming every RMS-200 has the same NVRAM capacity.
| Source | Published capacity |
|---|---|
| Radian product page, checked 2026 | 8GB standard; optional 16GB |
| Radian RMS-200 datasheet, version 1.7 (search record dates publication to 2014) | 2GB, 4GB, or 8GB DDR3 NVRAM |
How much SLOG capacity do you need?
Do not choose capacity as if a larger SLOG automatically makes ZFS faster. The FreeBSD Handbook says the log holds a short period of incoming writes and that a few gigabytes is generally sufficient; actual needs relate to the synchronous writes in flight and the workload. That is general guidance, not a universal sizing guarantee. (FreeBSD Handbook: ZFS)
Before buying an RMS-200, confirm its specific capacity and compare it with the needs of the workload. A card’s marketed capacity is not a performance multiplier.
Rank #3
- Accelerate your system with the Micron 5300 PRO SATA SSD and get the best combination of reliability, security, and solid performance
- Innovative 96-layer 3D NAND technology - increase storage density with 3.84TB of storage in a 2.5 inch form factor
- Comprehensive security - AES 256-bit encryption, power-loss protection, enterprise data path protection, adaptive thermal monitoring, and TCG Enterprise
- Enhanced Read Write speeds - sequential read and write performance levels of up to 540 MB/s and 520 MB/s
- Optimized to deliver high-performance for media streaming, OLTP, block and object stores, and business intelligence
What are the risks of a separate log device?
A SLOG participates in ZFS’s handling of synchronous writes, so its failure characteristics matter. The FreeBSD Handbook recommends mirroring log devices and describes the risk of losing an unmirrored log along with the system before logged writes have reached the main pool. The right layout depends on the system’s failure model; decide how much device redundancy is appropriate before putting a separate log into service. (FreeBSD Handbook: ZFS)
TrueNAS also describes the ZIL/SLOG role as protecting synchronous writes through a crash or power failure and advises checking the manufacturer’s power-loss-protection specifications. (TrueNAS: ZIL and SLOG) For an older card, documentation of the design is not a substitute for checking the exact unit’s condition and verifying stable-write behavior on the host.
Is the RMS-200 still a current product?
Radian labels the RMS-200 end of life and identifies the RMS-300 as its replacement. (Radian RMS-200 product page; Radian RMS-300 product page) Current stock, prices, and the condition of any used card are not established here. Treat the RMS-200 as a legacy product, not as hardware whose availability or support is assured.
Rank #4
- Compatibility: 2.5-Inch form factor size for capacity-dense storage, SATA III 6G interface
- Performance: storage space of 7680GB, qlc NAND flash Type for endurance & Performance
- Applications: real-time analytics, big data, AI data lakes, machine and deep learning
- Features: AES 256-bit encryption, power Loss protection, end-to-end data path protection
- Reliability: 24x7 availability, long-term lifespan, full Micron Warranty can be claimed through point of purchase
Before relying on one, verify the exact model and capacity, seller claims and card condition, physical PCIe slot and cooling needs, plus firmware and operating-system support for the specific server. No compatibility with a particular platform is established by the product information alone.
How to decide whether it fits your pool
- Confirm the workload. Determine whether the workload issues synchronous writes and whether their commit latency is limiting performance.
- Measure the existing pool. Record synchronous-write behavior and latency so that any improvement can be judged against the same workload.
- Verify the exact card. Check the RMS-200 variant, capacity, condition, PCIe fit, cooling, firmware, and host/OS support.
- Check durability and failure planning. Confirm the card’s power-loss behavior and decide how the log device fits the pool’s redundancy and recovery model.
- Evaluate the result under the target workload. Compare before-and-after performance; do not infer a ZFS benefit from vendor IOPS or throughput claims alone.
When comparing an RMS-200 with an RMS-300 or another candidate, prioritize synchronous-write latency and consistency at the target queue depth, documented power-loss behavior, exact host compatibility, capacity, redundancy, and lifecycle. Sequential throughput alone is not a meaningful SLOG comparison.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →
