Sandisk Optimus GX Pro 850P 2TB SSD review: A PS5 SSD you recognize at a price you don’t

Comparison Products

The Sandisk Optimus GX Pro 850P is Sandisk’s take on the WD Black SN850P, which in turn is a PS5 version of the Black SN850X, so we have to compare it to that latter drive. The stiffest proprietary competition is from Samsung with the 990 Pro. Alternatives with DRAM but different hardware include the Crucial T500, the Adata Legend 960 Max, the TeamGroup G70 Pro, and the Inland Gaming Performance Plus. To keep things honest, we also want to compare faster DRAM-less drives that have historically been great for the PS5. These include the Addlink A93 (4TB) and the WD Black SN7100.

Trace Testing — 3DMark Storage Benchmark

Built for gamers, 3DMark’s Storage Benchmark focuses on real-world gaming performance. Each round in this benchmark stresses storage based on gaming activities including loading games, saving progress, installing game files, and recording gameplay video streams. Future gaming benchmarks will be DirectStorage-inclusive and an evaluation for future-proofing is included where applicable.

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Is the 850P a good game drive? In our estimation, yes. It beats the original Black SN850X, due in part to firmware maturity and/or the newer BiCS5 – we would expect these two to be comparable if the Black is or has been updated – and it is also faster than popular DRAM-less options like the A93. In general, we think going with something DRAM-less, like the A93, is a good way to save some money if you’re buying an SSD just to host games. This approach extends even to the Black SN7100, which struggles on this list against the largely DRAM-equipped competition, as it still scores pretty well. We consider 45µs or better to be excellent for load times.

Trace Testing — PCMark 10 Storage Benchmark

PCMark 10 is an industry standard trace-based benchmark that uses a wide-ranging set of real-world traces from popular applications and everyday tasks to measure the performance of storage devices. The results are particularly useful when analyzing drives for their use as primary/boot storage devices and in work environments.

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For general application use, we are a little more disappointed. The 850P ends up in the middle of the pack, although its results are still quite good. This will beat most DRAM-less drives, although it falls behind the Black SN7100, as that drive uses very responsive BiCS8 flash. This makes it clear that the 850P is using older BiCS flash, which doesn’t have the same latency edge. This isn’t the worst trade-off if you’re looking for a full-fledged SSD with eight flash channels and DRAM – this drive will sustain better over time and through heavier workloads. Again, anything at or below 45µs for latency is good in our book, so this would be perfectly suitable as an OS drive.

Console Testing — PlayStation 5 Transfers

The PlayStation 5 is capable of taking one additional PCIe 4.0 or faster SSD for extra game storage. While any 4.0 drive will technically work, Sony recommends drives that can deliver at least 5,500 MB/s of sequential read bandwidth for optimal performance. Based on our extensive testing, PCIe 5.0 SSDs don’t bring much to the table and generally shouldn’t be used in the PS5, especially as they may require additional cooling. Check our Best PS5 SSDs article for more information.

Our testing utilizes the PS5’s internal storage test and manual read/write tests with over 192GB of data both from and to the internal storage. Throttling is prevented where possible to see how each drive operates under ideal conditions. While game load times should not deviate much from drive to drive, our results can indicate which drives may be more responsive in long-term use.

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The 850P should be, by most accounts, the definitive PS5 SSD. We’ve had the Black SN850X as our best SSD for the PS5 for quite a long time, although the SN850P is the PS5-specific model. The Black SN850X simply delivers a similar experience to the SN850P at a lower price point. Why is this the best SSD for the platform? Well, you get top-tier Gen 4 performance with reliability and an excellent heatsink. All of this still applies to Sandisk’s 850P.

Now, a DRAM-less alternative with half the flash channels – which means it runs cooler – like the A93 seems to be more sensible. It’s less expensive, and the PS5 doesn’t benefit from more performance than it provides. The argument here is therefore more on reliability and, possibly, consistency. The 850P can manage more flash at once – which actually is ideal for larger capacities, including 2TB for this generation – and it also has DRAM.

Many enthusiasts still want DRAM as it can improve performance and endurance. Keep in mind that our A93 sample is the 4TB model, which its controller can address thanks to a revision made for that purpose. A four-channel drive is still at its best with up to four dies per channel, or 16 in total, which works out to 2TB with 1Tb dies. Going past that doesn’t really deliver more performance, and having an eight-channel controller is preferable at higher capacities. A stronger argument would be this: the 850P is a quality, mature product that could act as an investment. Considering that a 2TB Black SN850X bought at its lowest price beats the stock market right now, that’s not as crazy as it once sounded.

Our take is that, for a PS5, you really can get anything. If you’re set on a quality drive, though, this one is basically as good as it gets. You’re here for the numbers, though, and it only wins in transfers to the drive, and not by much. That’s valid, but with more wear and a fuller drive, it is more likely to maintain peak performance for longer. So, don’t buy this drive for faster game load times or FPS, because you won’t get that here.

Transfer Rates — DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with a custom 50GB dataset. We write 31,227 files of various types, such as pictures, PDFs, and videos to the test drive, then make a copy of that data to a new folder, and follow up with a reading test of a newly written 6.5GB zip file. This is a real-world type workload that fits into the cache of most drives.

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Our DiskBench test gives a good measure of real-world performance with a mixed file load, with Gen 4 expectations around 2 GB/s for copies and writes and 4 GB/s for reads. Writes are going to be slower than reads and can help cap copy performance. The 850P does nothing unusual here, coming in at numbers close to these. We tend to put the most weight on copy performance and, here, the 850P manages to come in second behind only the T500. This makes sense as the T500 has newer flash with more planes, which helps it eke out more bandwidth. The Black SN7100 also has newer flash, specifically a newer form of BiCS, which keeps it competitive. Still, the 850P impressively beats the Black SN850X by a significant amount – perhaps due to firmware maturity and/or newer BiCS5 – and the 990 Pro as well.

This is an important result because most of what people use storage for ultimately comes down to transfers like these. Files between drives. Backups. Updating software. You’re not going to have a lot of transfers going on at once with a high queue depth, and if you’re working with smaller files, you are not going to get near the theoretical throughput. So, the 850P certainly earns the mantle of being a high-end Gen 4 drive. On the other hand, even the DRAM-less A93 is not that much slower. If you’re someone who does a lot of transfers, the added time could add up, though.

Synthetic Testing — ATTO / CrystalDiskMark

ATTO and CrystalDiskMark (CDM) are free and easy-to-use storage benchmarking tools that SSD vendors commonly use to assign performance specifications to their products. Both of these tools give us insight into how each device handles different file sizes and at different queue depths for both sequential and random workloads.

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The 850P performs very closely to the Black SN850X in ATTO, as expected. We see no real anomalies here. The drive is very consistent, which makes for a reliable user experience regardless of workload type. It is easy to notice, however, that the 850P and Black SN850X have weaker performance between the 512B and 2KiB block sizes, closer to the Legend 960 Max and WD Black SN7100. We would chalk this up to the controller technology for the WD and Sandisk drives – they all use proprietary ones with the same foundation – with the Legend 960 Max being the singular SMI-based drive.

We’ve found historically that drives may show up weaker here in ATTO as indicative of a trade-off. This is because, generally, we think in terms of 4KiB – a typical cluster and sector size that is used for performance metrics everywhere – which is a logical page downstream from the 16KiB physical pages that modern flash uses. Handling smaller reads/writes could increase memory load and can increase latency. However, focusing on 4KiB and larger block sizes makes more sense for a variety of workloads, and performance is not the only factor. A manufacturer also has to consider power consumption and wear, for example. So there may be good design reasons for this behavior.

If we move on to CDM to see performance at 4KiB, at a typical queue depth of 1, the 850P is average with reads and on top with writes. Anything at or below 45µs for reads is pretty good, and the drive competes well. The SN7100 is in a class of its own with its BiCS8 flash. For writes, which are often less important, we see strong numbers from most drives. The DRAM-less A93, the SMI-based Legend 960 Max, and the proprietary 990 Pro are on the weaker end. Generally speaking, this does not indicate a problem with the drive at this level and could be a facet of the controller, the flash, or both, often also as a trade-off. What we can say is that the 850P is stellar here, which certainly makes it more attractive for use in a NAS, for caching, and for workloads that are not found in the PS5. That’s not a knock – it simply illustrates the drive’s heritage and underlines that this drive could be good anywhere.

Sustained Write Performance and Cache Recovery

Official write specifications are only part of the performance picture. Most SSDs implement a write cache, which is a fast area of pseudo-SLC (single-bit) programmed flash that absorbs incoming data. Sustained write speeds can suffer tremendously once the workload spills outside of the cache and into the "native" TLC (three-bit) or QLC (four-bit) flash. Performance can suffer even more if the drive is forced to fold, the process of migrating data out of the cache in order to free up space for further incoming data.

We use Iometer to hammer the SSD with sequential writes for 15 minutes to measure both the size of the write cache and performance after the cache is saturated. We also monitor cache recovery via multiple idle rounds. This process shows the performance of the drive in various states including the steady state write performance.

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We’ll start with the 850P’s fastest mode in the cache: over 6.46 GB/s for just over 92 seconds. This is a 595GB cache, more or less exactly matching the Black SN850X. A drive with 3-bit TLC cache can handle up to one-third its actual size, so this is smaller than what’s possible but still large in the grand scheme of things. It’s more than suitably large to cache even large file writes, which means it can be used for things outside of gaming. This is reinforced by the post-cache speed, where it’s writing to the native TLC flash at a respectable 1.6 GB/s. This doesn’t sound like much given the speed of drives today, but it would be at or above the best Gen 3 drives in this mode while generally having a larger and faster cache.

Samsung’s 990 Pro is in the same boat, providing consistent performance outside the cache but looking slow compared to the steady state speeds we see with other drives. In part, this is due to the flash being used on it, as well as the WD/Sandisk drives. Newer flash has more planes and lower latency, both of which can boost throughput. Some drives, like the Inland Gaming Performance Plus, alternatively have smaller caches, which allow the drive to maintain higher sustained speeds. The same goes for the Legend 960 Max. Speed is also not everything, as not all drives write as smoothly in their post-cache modes. Maintaining responsiveness can help a drive feel spunkier when it hits this slower state.

If we take all of this into consideration, the 850P actually has some interesting applications. You could use this as a NAS drive, for example. Generally, we think the Inland Gaming Performance Plus – or the updated Performance Plus – would be better, as a super large cache leans more towards everyday consumer workloads. However, the 850P is steady enough with still sufficient speed. It would probably provide a better experience than the T500, especially as it has twice the flash channels, so it can manage better at high capacity. So, yes, this is a PS5 drive, but its heatsink and performance profile are such that you could use it as a workhorse drive as well.

Power Consumption and Temperature

We use the Quarch HD Programmable Power Module to gain a deeper understanding of power characteristics. Idle power consumption is an important aspect to consider, especially if you're looking for a laptop upgrade, as even the best ultrabooks can have mediocre stock storage in terms of capacity and performance. Desktops are often more performance-oriented with less support for power-saving features, so we show the worst-case for idle.

Some SSDs can consume watts of power at idle while better-suited ones sip just milliwatts. Average workload power consumption and max consumption are two other aspects of power consumption, but performance-per-watt, or efficiency, is more important. A drive might consume more power during any given workload, but accomplishing a task faster allows the drive to drop into an idle state more quickly, ultimately saving energy.

For temperature recording, we currently poll the drive’s primary composite sensor during testing with a ~22°C ambient. Our testing is rigorous enough to heat the drive to a realistic ceiling temperature, but real-world temperatures will vary due to the environment and workload factors.

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The 850P has a heatsink, so it’s not going into a laptop, and concerns about power consumption are a little less important. The presence of the heatsink also helps keep the drive cool, so throttling is also not a big concern. Still, you could choose to remove the heatsink, and maybe you want to toss this into a small form factor media machine. In those cases, the 850P’s efficiency – which lands in the lower half of the pack – is sufficient but not great. It’s better than the SM2264-based Legend 960 Max and E18-based Gaming Performance Plus, which are good baselines, but falls behind newer drives and technology.

Our feeling here is that a high-end Gen 4 drive should get at least 400 MB/s per watt, which is generally the case. DRAM-less options can target much higher and are often a better choice if you’re worried about heat or power consumption. If you are going for a high-end drive, ideally you have a heatsink. The one the 850P comes with is very effective, with us measuring a maximum temperature of 54 degrees Celsius. This is very far off from throttling and, frankly, it is a fantastic result.

Test Bench and Testing Notes

We use an Alder Lake platform with most background applications such as indexing, Windows updates, and antivirus disabled in the OS to reduce run-to-run variability. Each SSD is prefilled to 50% capacity and tested as a secondary device. Unless noted, we use active cooling for all SSDs.

Sandisk Optimus GX Pro 850P Bottom Line

The Sandisk Optimus GX Pro 850P brings no real surprises. If you were expecting it to be a WD Black SN850P – which itself is just a Black SN850X with a PS5-compliant heatsink – with a Sandisk badge, then you won’t be disappointed. Technically, there are some firmware optimizations possible for a drive destined to be used in PS5s, but we’ve found that any such changes have little impact on overall performance. The 850P is a drive with mature hardware and firmware, and that’s the main story here. It’s a reliable, consistent, well-performing drive that will rock the PS5 but is also good in regular computers.

Our biggest complaint is probably that the 850P can be bested by other drives in any given category. There are less expensive drives with similar performance in the PS5. There are drives that will be better in a laptop, even assuming the 850P’s heatsink is removed. There are even drives that beat it on the desktop in some areas, or are less expensive. Frankly, it feels like a premium drive, and that’s long been the case for the Black SN850X and its progeny. This is also true of the Samsung 990 Pro, its direct competitor, and there’s nothing wrong with that. If you want a rock-solid drive that can do anything, look no further. If you have a specific application in mind or want to save some money, there are other options.

Considering how much people value their data and worry about storage stability, we think the Optimus GX Pro 850P does have a place. It’s a no-nonsense drive that gets the job done with a proven track record. The heatsink is very effective, and the drive itself doesn’t really struggle with any one workload. While it is designed for the PS5, it would be plenty happy in an enthusiast’s desktop. Not everybody needs a Gen 5 powerhouse. We recommend it for the discerning buyer who wants something fast and reliable without having to guess what hardware is inside some generic brand’s drive.

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