WD My Cloud EX4100 Reviewed

Photo of author

Tim Higgins

My Cloud Expert Series
At a glance
Product Western Digital My Cloud Expert Series (EX4100) [Website]
Summary Four-bay dual-core Marvell NAS with personal cloud, media serving & business features
Pros • Dual Gigabit Ethernet ports
• USB 3.0
• Remote access without port forwarding
• 10 licenses for Smartware Pro backup software
• Dual-power option
Cons • Rsync backup not supported
• Can’t schedule backup to external devices


WD’s My Cloud EX4100 is a downmarket Marvell-based version of the top-of-line Intel Atom based My Cloud DL4100 reviewed a few months ago. There’s also the two-bay EX2100 we won’t be reviewing, if you prefer your NASes in RAID 1 form with a slightly slower processor and half the memory.

WD sent a 16 TB WDBWZE0160KBK model as our review sample. But the EX4100 also comes in diskless (WDBWZE0000NBK), 8 TB (WDBWZE0080KBK) and 24 TB (WDBWZE0240KBK) models. As we did with the DL4100, we’re showing the 0 TB BYOD model for pricing, so you can more easily compare to other BYOD NASes. WD uses the “Red” series of NAS-optimized hard drives for all diskful My Cloud SKUs.

The EX4100 and DL4100 share the case design shown in the callout graphics below, pulled from the DL4100 review.

WD My Cloud EX4100 front panel callout

WD My Cloud EX4100 front panel callout

The only difference is the EX4100 has all USB 3.0 ports vs. the DL4100’s two USB 3.0 and one USB 2.0. You can get complete charts for LED status (front and rear panel) from the User Manual here. The EX4100 also uses tool-less, tray-less drive bays.

WD My Cloud EX4100 rear panel callout

WD My Cloud EX4100 rear panel callout


Table 1 shows the key components for the My Cloud EX4100, DL4100 and EX4. The dual-core Armada 388 is a big step up from the single-core Kirkwood and it shows in the performance results.

WD My Cloud EX4100 WD My Cloud DL4100 WD My Cloud EX4
CPU Marvell dual-core Armada 388 @ 1.6 GHz Intel dual-core Atom C2338 @ 1.7 GHz Marvell Kirkwood 88F6282A1 @ 2.0 GHz (single-core)
RAM 2 GB DDR3 (Hynix H5TQ4G83AFR x4) on board
not upgradable
2 GB DDR3 (Micron MT41K256M8DA x8) on board upgradeable to 6 GB via SoDIMM DDR3 1600MHz 512 MB DDR3
Flash 512 MB Hynix H27U4G8F2DTR 512 MB Micron 29F4G08ABAEA
8 MB Winbond 25Q64FVIG
256 MB
Ethernet Marvell 88E1512 (x2) Marvell 88E1512 (x2) Marvell 88E1518-NNB2 (x2)
SATA In CPU In CPU Marvell 88SX7042
USB 3.0 Renesas D720120 Asmedia ASM1042A Etron Tech EJ168A
Table 1: Component summary comparison

The photo below shows the EX4100’s board. The processor heatsink is kind of interesting. It’s a hollow aluminum cube with a thermal pad taped on top for a little extra thermal mass.

WD My Cloud EX4100 PCB component side
WD My Cloud EX4100 PCB component side

The DL4100’s board is shown below for comparison. What you can’t see is the single SODIMM slot on the other side of the board that supports DDR3 RAM expansion up to 6 GB total. The EX series RAM is all on board and there’s no expansion slot. The EX models also dispense with the buzzer, so no audio alerts. They keep the LCD front panel display, though.

WD My Cloud DL4100 PCB component side
WD My Cloud DL4100 PCB component side

Fan and drive noise was rated low. Power consumption for the external “brick” power supply was measured at 29 W (active) and 12 W (power save) with the four factory installed 4 TB WD Red (WD40EFRX) drives.


All My Cloud share a common OS, so have the same features. The only difference is supported RAID modes, which depend on the number of drive bays. I won’t repeat the feature rundown provided in the DL4100 review.


The EX4100 was tested with 1.06.127 firmware using our Revision 5 NAS test process. The EX4100 tests used four drives configured in single RAID 0, 5 and 10 volumes. All tests were run using factory-installed Western Digital Red 4 TB (WD40EFRX) drives.

It’s getting harder for NASes to differentiate themselves on performance, since even lower-end SoC-based products can max out a single Gigabit Ethernet connection for large sequential file transfers. That’s just what the File Copy Write / Read charts for all RAID 5 products below show.

Even though the EX4100 sits lower in the charts, keep in mind its 110 MB/s write and 106 MB/s read results are within 5% of the 110 MB/s top result. That’s equal as far as I (and the NAS Ranker) am concerned!

Four drive NASes - File Copy Write (l) and File Copy Read Performance

Four drive NASes – File Copy Write (l) and File Copy Read Performance

The Benchmark Summary shows different results for the NASPT File Copy tests due to its use of a single 1.15 GB Windows backup file vs. the 4.35 GB folder of ripped DVD files. But for all intents and purposes, the EX4100 pretty much hits the limit of what a single Gigabit Ethernet port will support when moving large media files. Remember aggregating ports helps only if you use multiple clients and connect to a switch that also supports port aggregation.

WD My Cloud EX4100 Benchmark Summary

WD My Cloud EX4100 Benchmark Summary

Performance Ranking

The NAS Ranker does a better job of comparing overall performance because it takes multiple benchmarks into account. We’ve found sorting by ascending price helps quickly home in on the best value products.

Doing this finds the EX4100 four steps up from the Thecus N4310 least expensive RAID 5 NAS, but with the highest performance rank of #8. This makes the EX4100 the best combination of price and performance in a RAID5 NAS! You need to move five steps down to find the #7 ranked DL4100 because it currently will run you around $510; about $125 more.

RAID5 NAS Ranking

RAID5 NAS Ranking

If you’re still trying to decide whether the extra $125 or so is worth it for the DL4100, the NAS Ranker Performance Summary below should help. The DL4100 ranks higher for Read performance. But looking at the throughput numbers themselves says to me it’s doubful you’d see a significant difference in real world use. The EX4100 actually does better in the mixed read/write and video tests. But the DL4100 spanks the EX for USB 3.0 backup and does a bit better for iSCSI.

Ranker Performance Summary comparison

Ranker Performance Summary comparison

Closing Thoughts

While some might agonize over the choice, it’s pretty clear to me that WD’s EX4100 is the pick of the My Cloud litter when it comes for best price / performance in a mid-range RAID 5 NAS. Maybe that’s why it’s for "Experts".

Related posts

Trendnet TS-I300: Simple, pricey BYOD NAS

Craig Ellison finds that Trendnet's TS-I300 is a decent, but a tad expensive entry-level NAS.

HP Media Vault Pro Review: Small-biz NAS for HP fans

HP bumps capacity to 1 TB, adds an online backup service and takes away the movies from its Media Vault and says it has a nice small business NAS. Bill Meade agrees...except for the bugs and undocumented features.

Seagate Personal Cloud 2-Bay Reviewed

The Seagate Personal Cloud 2-Bay brings RAID 1 to Seagate's new home NAS family.