Unsavory Flash Swap: Re-Testing Crucial’s P2 SSD After QLC Downgrade

Comparison Products

Today, we put Crucial’s new 500GB QLC-based P2 against its TLC-powered predecessor as well as a bunch of the best SSDs available. This comparison includes the Samsung 980 Pro, Sabrent Rocket NVMe 4.0, SK hynix Gold P31, Samsung 970 EVO Plus, Samsung 980, Seagate BarraCuda 510, and WD Blue SN550.

Game Scene Loading - Final Fantasy XIV

Final Fantasy XIV Shadowbringers is a free real-world game benchmark that easily and accurately compares game load times without the inaccuracy of using a stopwatch.

Game load performance is one of the only metrics in which the new variant has improved, but the difference is so minuscule we could blame newer, more optimized firmware or run-to-run variance as the reason for the TLC variant’s loss – we’re looking at a 0.05 second difference between the two drives. 

In either case, both P2 variants trail the comparison pool with the slowest times by a large margin, making them both subpar for game loading. 

Transfer Rates – DiskBench

We use the DiskBench storage benchmarking tool to test file transfer performance with a custom dataset. We copy a 50GB dataset including 31,227 files of various types, like pictures, PDFs, and videos to a new folder and then follow-up with a reading test of a newly-written 6.5GB zip file.

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The QLC-based P2 delivered terrible performance during our real-world transfer test, which involves copying a 50GB file folder and reading back the test file. These are the types of real-world activities that are ubiquitous on PCs the world over, but you’ll take a significant performance haircut with the QLC P2. 

The SSD could only muster up enough speed to copy the folder at a rate of 98 MBps, which is roughly one-quarter the speed of the original TLC-powered model. The drive also reads back large files at half the speed of the TLC variant, too.

Trace Testing – PCMark 10 Storage Test

PCMark 10 is a 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 quick benchmark is more relatable to those who use their PCs for leisure or basic office work, while the full benchmark relates more to power users.

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When tasked with light loads, the new QLC variant of the P2 delivers similar performance to its predecessor, scoring just a few points below in the Quick System Drive Benchmark. 

However, when tasked with the Full System Drive Benchmark tests, the QLC variant fell flat with roughly 40% lower performance. Latency, the most important metric for an SSD, was also three to four times higher than any other competitor. 

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.

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Based on the ATTO benchmark alone, it looks like the P2 should perform better than its predecessor, but unfortunately, this didn’t carry over into other tests because ATTO tests with fully compressible data, which is mostly unrealistic. Crystal Disk Mark’s results, on the other hand, show the new P2 delivers slower sequential performance with incompressible data, which more closely aligns with the data most people store on their PC. 

Additionally, the QLC-powered P2’s random performance at a queue depth of 1 (QD1) remains close to the TLC variant, but the QLC model severely lags at higher queue depths, delivering one-third to half the speed.

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 (usually) pseudo-SLC 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 or QLC flash. 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.

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One improvement, at least to some degree, is the increased SLC cache capacity. The TLC variant’s SLC cache measured only 24GB, while the QLC replacement’s cache measured roughly 135 GB. Still, while the capacity has increased in an attempt to offset the impact of the much slower QLC flash, the speed of the P2 degraded severely both within and outside of the SLC cache. Some of this goes back to the reduced number of packages, which hampers interleaving, and thus parallelism. 

Our TLC-based P2 wrote at roughly 1.85 GBps while the QLC-based P2 wrote at 1.16 GBps before degrading. Once degraded, the TLC variant's sustained write speeds measured roughly 450 MBps, which isn’t great, but acceptable. However, the QLC variant averaged USB 2.0-like speeds of just 40 MBps after the SLC cache was full.

Power Consumption

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. 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 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.

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Not only did the P2’s performance go down the drain, but so did power efficiency. While the average power consumption dropped during our 50GB file test in comparison to its predecessor, the new QLC-based P2 scores the lowest efficiency out of the test pool.

Test Bench and Testing Notes

We use a Rocket Lake platform with most background applications such as indexing, windows updates, and anti-virus 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.

Bottom Line

Crucial’s planned component changes may have been part of a strategic plan to more efficiently utilize its resources in its products, probably to both save money and to assure supply, but the manner of execution is important. Unfortunately, this business tactic has resulted in truly abysmal performance compared to the original model, thus drastically reducing the value proposition of buying the P2. 

You wouldn’t know that, though, if you hadn’t read this article: Every review that you see of the P2 has higher performance values than what you’ll see with the new models. There’s no way to tell which drive is which, so it’s best to assume that all P2 SSDs on the market come with QLC flash now, and the Crucial P2 won’t live up to its billing in the numerous product reviews you’ll find on the internet.

We no longer recommend Crucial’s P2 for those seeking a value-level SSD. Rather, we would go as far as to place it on our ‘do not buy’ list. 

While component changes can be deemed acceptable in certain circumstances, they require proper disclosure and shouldn’t come after reviews of the same device show it has much better performance than the ‘new’ version. In those cases, the company should issue a new model number. 

The new P2 offers nowhere near the same level of performance as its predecessor in most situations, and it already severely lagged the competition in the areas that remain unchanged. For those considering the P2, please steer clear and opt for one of our Best SSD recommendations instead.

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