Best NVMe SSD for NAS Cache: Compare WD Red SN700, Samsung 970 EVO Plus, and Crucial P3 Plus

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Choosing a cache SSD for a NAS is less about chasing the biggest sequential-read number and more about matching the drive to the kind of churn the cache layer will see. A light read cache for a media library has a different risk profile from a busier mixed-use NAS that keeps rewriting thumbnails, metadata, and small random blocks all day.

That makes endurance, sustained write behavior, and controller design more useful filters than marketing language alone. A NAS-rated drive can justify its price when the cache sees constant write activity, while a cheaper consumer NVMe drive can still fit perfectly well when the workload stays lighter and the budget is tighter.

This page helps a homelab operator choose between WD Red SN700, Samsung 970 EVO Plus, and Crucial P3 Plus by focusing on the cache behaviors and purchase tradeoffs that cited product documentation actually supports.

Quick comparison table

The table already tells most of the story.

The Crucial drive looks fast because Gen4 numbers are easy to market. The WD drive looks slower because PCIe 3.0 is older. But NAS cache is not a desktop benchmark contest. It is a consistency, endurance, and latency problem.

That is why the Samsung and WD drives are still the serious contenders.

What NAS cache actually rewards

SSD cache helps when your NAS is serving lots of small, repeated requests: - Synology Photos or Immich thumbnails - VM disk metadata - Docker volumes and app databases - office shares with many tiny files - active working sets that fit in cache

It helps much less when your NAS mostly does: - big Plex movie reads - nightly backup dumps - large archive storage - sequential media copies over a 1GbE link

If you are still figuring out the wider storage design around your cache layer, read Proxmox Storage Architecture: The Layout I Actually Recommend and ZFS vs Btrfs vs ext4 first. Cache is not magic. It only helps when the rest of the storage design makes sense.

How published cache benchmarks map to NAS behavior

Spec sheets are abstract, so I translated the published write speeds into a simple 250 GiB cache-fill scenario.

These are best-case theoretical write times, not a promise that your NAS will hit them during every operation.

This is exactly why peak write speed can mislead you.

Yes, the Crucial P3 Plus is fastest in this synthetic framing. But the difference between 64 seconds and 89 seconds is not the thing most homelab buyers will notice day to day. What they notice is whether the drive stays responsive under constant mixed I/O, whether it wears out early, and whether it behaves predictably inside a cramped always-on NAS chassis.

Endurance is where the buying decision gets real

This is the section most listicles soften because the answer gets inconvenient.

If you run a read-only cache, endurance is usually not the limiting factor. If you run read-write cache, endurance becomes the whole ballgame.

Using the published TBW ratings, here is how the three drives look if your cache absorbs roughly 100 GB/day of writes versus a heavier 400 GB/day:

That table is why WD Red SN700 remains compelling even when its peak speeds are lower.

A NAS cache drive is not a boot SSD that spends half its life idling between browser launches. It is sitting in a 24/7 box that may be chewing through photo indexing, sync jobs, metadata churn, or VM activity all day. Endurance matters more here than it does in a gaming rig.

Samsung 970 EVO Plus: the best overall pick

The data says Samsung wins for most people because it hits the best middle ground.

Tom's Hardware rated the 970 EVO Plus as one of the fastest PCIe 3.0 SSDs of its class and highlighted its strong overall performance, solid efficiency, and mature software stack. The drive also carries a DRAM cache, which matters for NAS usage more than many buyers realize.

On the 2026 SERP, HomeLabPicks makes the strongest practical case for Samsung as the all-around cache winner: DRAM-backed designs maintain low latency more gracefully under constant random I/O, while DRAM-less HMB designs can spike much harder when the workload gets messy.

That lines up with the kind of tasks homelabs actually throw at a cache drive: - photo libraries - app metadata - containers - VM-related small-file churn - lots of repeated random reads

Pros

• DRAM-backed design is a better fit for mixed random I/O than cheap DRAM-less budget drives
• 3,500 / 3,300 MB/s is still plenty for NAS cache roles
• 620K / 560K random IOPS gives it strong responsiveness where cache matters most
• 600 TBW is not elite, but it is still healthy for most home use
• mature firmware and broad real-world compatibility

Cons

• lower endurance than the WD Red SN700
• no NAS-specific branding or positioning
• pricing is sometimes awkward if the SN700 is discounted nearby

Who should pick Samsung 970 EVO Plus

Pick it if: - your NAS cache is mostly accelerating home-lab responsiveness, not taking punishment from heavy write-back workloads - you want the best all-around compromise between latency behavior, price, and reliability - you are running Synology, QNAP, or DIY NAS builds with mixed app and small-file traffic

For many homelab readers, Samsung 970 EVO Plus remains the broad default pick because its price, DRAM-backed design, and mature platform support stay well balanced for lighter or mixed cache duty.

WD Red SN700: the best endurance-first NAS pick

WD did the obvious smart thing here. Instead of chasing bigger desktop benchmark headlines, it built a drive that makes more sense in sustained NAS duty.

Tom's Hardware called the SN700 unexciting in pure general-use performance, but also praised its consistency, strong sustained workload behavior, and efficiency. That is exactly the kind of boring I want in a NAS cache drive.

The SN700 is rated up to 2,000 TBW at 1TB and scales all the way to 5,100 TBW on the 4TB model. That is not a small advantage. It is a category-defining one.

WD Red SN700 fits best when the cache is expected to absorb heavier daily write churn rather than mostly light read acceleration.

Pros

• much stronger endurance than Samsung 970 EVO Plus and especially Crucial P3 Plus
• purpose-built NAS positioning is actually meaningful here
• strong sustained-workload reputation from SSD reviewers
• 5-year warranty and capacity options up to 4TB
• safer pick for read-write caching

Cons

• slower than the others on peak sequential write numbers
• weaker value if your cache workload is mostly read-heavy and light
• usually not the cheapest option per TB

Who should pick WD Red SN700

Pick it if: - you are using read-write cache, not just read cache - your NAS hosts Docker databases, surveillance metadata, active sync workloads, or VM-heavy traffic - you want a conservative endurance-first decision and do not care about winning a desktop benchmark chart - you are the type of buyer who would rather overbuy endurance now than replace a dead cache SSD early

If your stack also includes protocol-heavy file serving, NFS vs SMB vs iSCSI is worth reading alongside this purchase decision. Protocol choice and cache choice often get blamed for each other's problems.

Crucial P3 Plus: the budget answer with real caveats

This is the one people want me to bless because the price is attractive and the sequential spec sheet looks fantastic.

I get it.

At 1TB, the P3 Plus posts 5,000 / 4,200 MB/s sequential numbers and often costs dramatically less than NAS-focused alternatives. Tom's Hardware also described it as efficient and good value for capacity. If you stop there, it looks like the obvious buy.

But the caveat is not small: this is a QLC, DRAM-less, lower-endurance drive. Tom's also flagged the lower endurance as a core downside, and HomeLabPicks is blunt about the broader problem with cheap DRAM-less cache candidates - they can look fine in short desktop tests yet behave worse under constant random NAS workloads.

At 220 TBW for the 1TB model, the endurance story is not in the same league as the other two drives.

Pros

• usually the cheapest way into 1TB NVMe cache capacity
• fastest headline sequential numbers in this three-way comparison
• good enough for lighter read-heavy cache roles
• 5-year warranty is still respectable

Cons

• dramatically lower endurance than WD or Samsung
• QLC and DRAM-less design are not what I want for heavier mixed cache abuse
• weaker long-term value if the drive ends up wearing out early
• much easier to recommend for secondary or light-duty use than for serious 24/7 cache work

Who should pick Crucial P3 Plus

Pick it only if: - you are building a budget box - your cache role is mostly read-heavy - your write volume is light - you understand that the low price is buying a compromise, not a hidden bargain miracle

For a lighter home backup NAS, a lower-cost drive can be acceptable; for a busier mixed-use lab, paying for the higher-endurance option once is usually easier than replacing a marginal cache drive early.

Who wins by use case?

Is SSD cache even worth it?

Sometimes yes. Sometimes absolutely not.

If the NAS mostly serves large sequential media files, the better upgrade may be networking, memory, or the base HDD layer rather than adding SSD cache simply because an M.2 slot is available.

But if your box also runs apps, thumbnails, databases, sync jobs, or VM-related metadata, SSD cache is one of the few upgrades you can actually feel immediately.

That is also why I would pair this article with WD Red Plus vs Seagate IronWolf vs Toshiba N300. The HDD layer still matters. Cache does not rescue a poor base storage choice.

Recommended affiliate picks

Before you buy, it is worth checking whether Coupert can surface a working coupon or cashback offer for the store you are using. If you are already price-checking this cache SSD, you can try Coupert to see whether there is an extra discount or cashback available at checkout.

If you want the short shopping list, start here:

• WD Red SN700 1TB on Amazon
• Samsung 970 EVO Plus 1TB on Amazon
• Crucial P3 Plus 1TB on Amazon

In short: choose Samsung 970 EVO Plus for the broad default case, WD Red SN700 for endurance-first cache duty, and Crucial P3 Plus only when the budget matters more than long-write headroom.

Recommended default pick

For most HomelabAddiction readers, Samsung 970 EVO Plus wins.

It is the best mix of responsiveness, random performance, mature platform behavior, and reasonable endurance. It feels like the most balanced recommendation because it does not over-index on one metric while quietly failing another.

Endurance-first pick: WD Red SN700 fits best when heavier write churn matters more than lowest initial cost.

Budget-first pick: Crucial P3 Plus can fit lighter read-heavy cache duty, but its lower endurance makes it harder to justify for heavier mixed-use NAS churn.

That is the real conclusion here: the best NAS cache SSD is not the one with the biggest spec-sheet read number. It is the one whose latency behavior, endurance, and sustained consistency actually match a 24/7 cache workload.

For most people, that still points to Samsung. For harder-duty buyers, WD is the smarter answer.

FAQ

Is WD Red SN700 better than Samsung 970 EVO Plus for NAS cache?

For heavier read-write cache use, yes. The WD Red SN700 has a much stronger endurance rating and a more NAS-specific sustained-workload story. For most mixed home-lab use, Samsung 970 EVO Plus is the better overall value and still the better overall recommendation.

Is Crucial P3 Plus good enough for Synology or TrueNAS cache?

It can be good enough for light read-heavy cache duty, but it is harder to justify for heavier 24/7 mixed workloads because the 1TB model's 220 TBW endurance is much lower than the other two drives here.

Does DRAM matter for a NAS cache SSD?

Yes. DRAM matters more in NAS cache than in many desktop use cases because cache workloads often involve constant small random I/O. DRAM-backed drives generally handle that type of pressure more gracefully than cheaper DRAM-less alternatives.

Should I buy a Gen4 SSD for NAS cache if my NAS only supports PCIe 3.0?

Not automatically. If the Gen4 drive is cheaper and durable enough, fine. But do not pay extra for headline Gen4 numbers your NAS cannot use. Endurance and consistency matter more than interface bragging rights in most cache roles.

Is SSD cache worth it for Plex alone?

Usually not for pure media streaming. Plex benefits more from CPU, networking, and media-drive choices unless your NAS is also handling thumbnails, metadata, downloads, and lots of concurrent small-file activity.