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512GB Performance Testing
Comparison Products
The reference design SM2263XT SSD we tested in our preview article provided solid performance. As such, we didn't change our charts up too much to highlight the entry-level nature of the EX900, although we did add the MyDigitalSSD SBX. The SBX is another low-cost NVMe SSD, but it has a DRAM package.
The Intel 760p falls into the low-cost category even though the HP EX920 SSD costs less and delivers slightly more performance with the same controller and similar flash. The Samsung 960 Pro is a fixture in the ultra-high-performance market, but you'll have to spend more to bask in its performance. The Samsung PM981 has transformed from a unicorn to a popular OEM SSD that makes an appearance in several new notebooks.
The Corsair NX500 has just 400GB of usable capacity, while the Plextor M9Pe, Toshiba RD400, and Western Digital Black PCIe round out the test pool.
Sequential Read Performance
To read about our storage tests in-depth, please check out How We Test HDDs And SSDs. We cover four-corner testing on page six of our How We Test guide.
Most of the next-gen DRAMless SSDs we've tested don't scale well as we increase load. Instead, they are strong at low queue depths (QD), which is good considering the target market. The 500GB EX900 delivers a steady yet strong 2000 MB/s across the QD range, but it dips slightly under extreme load.
Remember, the EX900's goal isn't to be the best: it just has to be better than SATA SSDs at similar price points. The drive we're testing today reads sequential data nearly four times faster than many SATA SSDs.
Sequential Write Performance
We measured the EX900's sequential write performance at a steady ~1500 MB/s. This is much higher than anyone could reasonably expect given its price point. This is a burst test though, so don't expect this performance over the long haul if you're writing very large files to the drive.
Sustained Sequential Write Performance
The EX900 500GB does use a large SLC cache that spans around 15% of the overall capacity if you have very little data on the drive. The dynamic cache shrinks as you add data, but the 12GB of overprovisioning ensures you will have ample SLC cache for most file transfers.
Random Read Performance
The DRAM-less EX900 performs well during random read workloads at low queue depths. The drive scored nearly 12,000 IOPS at QD1 and scaled well up to QD8. These are the most common depths for consumer workloads, so we're not as focused on the high queue depth range.
Random Write Performance
DRAMless SSDs always struggle in random write workloads compared to products outfitted with DRAM. The SM2263XT controller makes good use of the small SRAM cache inside the controller, which helps boost performance at low queue depths.
70% Mixed Sequential Workload
We describe our mixed workload testing in detail here and describe our steady state tests here.
The EX900's mixed sequential performance holds steady at 1,000 MB/s throughout the test. The drive doesn't gain any performance as we ramp up the workload.
70% Mixed Random Workload
The same results also happened in the mixed random test. We're less enthusiastic about the results of this test, though. The sequential results are low compared to other NVMe SSDs, but the random results are even more out of proportion. The EX900 simply cannot scale as we lean on it with heavier workloads.
Sequential Steady-State
This drive wasn't built for heavy workloads. The low endurance rating will keep many enthusiasts and professional users from using it for heavy AV editing. The performance is surprisingly good in the two breakout tests, but you don't want to get this drive into a steady-state, which you'll see later in the review.
Random Steady-State
The random write steady-state test also brings another surprise. The drive is very consistent, but the performance is also very low due to the drive reaching out to the system RAM for the map of addresses.
PCMark 8 Real-World Software Performance
For details on our real-world software performance testing, please click here.
The EX900 doesn't win any performance contests with real-world applications. The drive doesn't have to either, as long as HP can get the price in line with SATA SSDs. Currently, the EX900's performance isn't in line with its pricing.
Application Storage Bandwidth
SSDs that use the Phison PS5008-E8 controller, like the MyDigitalSSD SBX, and variants from Kingston and Patriot, perform a little better than the EX900. The 512GB SBX currently sells for just $159.99 on Amazon, so it also costs less than the EX900. The Kingston and Patriot aren't as inexpensive as the SBX, so they don't provide the same value.
PCMark 8 Advanced Workload Performance
To learn how we test advanced workload performance, please click here.
As we mentioned, the 500GB EX900 falls flat during very heavy workloads. Unlike the EX920 we tested, this series does recover quickly after heavy workloads. The EX900 trails several of the other products during the recovery stages, but it's not the slowest NVMe SSD on the market.
Total Service Time
The EX900 has slightly elevated latency as it recovers from the heavy workload, but it isn't as high as the DRAM-less SATA SSDs of yesteryear. This represents a massive improvement for this product category.
Disk Busy Time
The disk busy time test shows us how long the HP EX900 500GB had to actually work to complete the workloads in each series of tests. During heavy use, the drive spends a lot of time pushing data to the waiting system. The EX900 responds much faster after a five-minute idle time because the controller has time to clean cells that are later used to write data at high speeds.
BAPCo SYSmark 2014 SE Responsiveness Test
The HP EX900's biggest competitor comes in the form of the Phison PS5008-E8 products, like the MyDigitalSSD BPX. The EX900 does provide a slightly better user experience than the MyDigitalSSD SBX. However, there are cheaper products that perform better than the EX900.
BAPCo MobileMark 2012.5 Notebook Battery Life
To learn how we test advanced workload performance, please click here.
DRAM is power hungry, and removing the chip makes a reasonable case for lower power consumption than DRAM-equipped SSDs. In fact, that was a big part of the initial DRAMless marketing push.
We found the opposite. The DRAM-less SSD do have lower idle and active power consumption, but in practice, the drives take longer to complete tasks, so they work longer. That means the drive spends less time sipping power at idle. DRAM-less SSDs also take longer to perform background activities, which is the work you don't see and very few actually measure. Garbage collection, which is one of the most prevalent background tasks, chews through a lot of power. That's why DRAM-less SSDs typically don't provide the power-to-performance ratio you would expect.
The EX900 does pretty well in our Lenovo Y700-17 gaming notebook. We measured more than five hours of battery life during MobileMark's test suite.
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