Best SSD as a Boot Drive

Hello!

I have built a pretty high-end consumer PC.

As boot drive & storage, I am using 3x Samsung 970 Pro 1TB (M.2 NVMe PCIe 3.0 x4) SSDs in RAID-0.

I’d like to change my boot drive, and to go with a very fast one.

I’ve set my eyes on these 3 drives:

  1. Crucial T705 4TB (M.2, Gen5, 4GB DRAM Cache, 440GB pSLC NAND Cache, 2400TBW).

  2. Corsair MP700 Pro SE with Air Cooler (M.2, Gen5, 8GB DRAM Cache, 440GB pSLC Cache, 3000TBW).

  3. Solidigm D7-P5810 / SSDPF2SQ800GZ01 (800GB, Enterprise drive, U.2, Gen4, SLC, Endurance: 50X Drives/Day).

Question:
Which drive would be the fastest?

Neither if your mainboard doesn’t support PCIe Gen4 or 5 :roll_eyes:

Assuming your system does have PCIe Gen5 onboard, I’d favour the Corsair drive.

Having said that, personally I’d go with a larger drive (1TB or more) with lower speed (PCIe 3 or 4) for less money as there’s really no noticeable advantage in boot times past PCIe Gen 3: it’s the OS that takes time booting itself, not so much the hardware. And by leaving a large section of the large drive unused, the controller on it has more reserve cells to work with, thus prolonging the life of said drive.

HTH!

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You gotta define “fast.”

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I agree wholeheartedly with this advice.

Any 3.0 or 4.0 NVMe SSD with TLC and DRAM cache is going to be fast enough. We’re talking shaving off something like 2%-3% more while spending twice the money to do it for a faster drive.

Heck, some TLC non-DRAM drives are reaching decent performance now - like the 2TB MP44L which is not that far behind, say, a Samsung 980 Pro. If you combine it with an OS that tightly integrate their packages, like Debian or Arch, it’s even possible to run the entire OS on a RAMdisk with 16 GB of storage or so, negating the need for a fast drive completely. Can’t do that on Windows unfortunately, since every Windows app carry all their own dependencies you’d need something like 500 GB of RAM to do that comfortably.

Case in point, my current df -h results on debian (no, not in RAMdisk… yet, reordered for better readability), this includes Steam and all dependencies of Steam:

Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p1  511M  4.4M  507M   1% /boot/efi
/dev/nvme0n1p2   28G  9.6G   17G  37% /
/dev/nvme0n1p4  1.8T  324G  1.4T  19% /home
/dev/sda1       880G  630G  205G  76% /mnt/extra
efivarfs        128K   16K  108K  13% /sys/firmware/efi/efivars
udev             31G     0   31G   0% /dev
tmpfs            31G     0   31G   0% /dev/shm
tmpfs            31G   20K   31G   1% /tmp
tmpfs           6.2G  2.3M  6.2G   1% /run
tmpfs           5.0M   20K  5.0M   1% /run/lock
tmpfs           6.2G  2.8M  6.2G   1% /run/user/1000
tmpfs           1.0M     0  1.0M   0% /run/credentials/systemd-journald.service

Hello!

Thanks for the reply.

I did not specify, but my motherboard does support PCIe 5.0.

As you can see, the two M.2 drives, that I’ve set my eyes upon, are 4TB large, only the Solidigm U.2 drive has 800GB storage.
However, the Solidigm drive uses 1-bit SLC NAND, while the other 2 drives are using 3-bit TLC NAND.

In the end for boot drive there will be marginal difference between any of your candidate drives, as target workload is low QD random reads.

PCI gen doesn’t matter here, it is not and never was a bottleneck, flash itself and its random read 1QD1T performance + latency is.
random read 4k QD1T1 performance + latency is is also a performance metric that hasn seen any significant improvement in long time and none is on the horizon for NAND flash.

If you are that kind of speed freak, get legacy optane, its head and shoulders better in this scenario.

If optane is off the table, next best is D7-P5810 , amazing if extreme overkill drive. Perceptible perf gain will likely be minimal or outright nonexistent vs middle tier consumer drives.

pSLC drives are the best NAND ssd from this perf standpoint, but perf difference is not that great when compared to massive cost increase.

vs

around 1/5 of optatne performance at 4k RR and low QD.

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This is not as close to the Intel Optane that its name is suggestive of replacing. I believe it may actually be QLC run as pSLC. Kioxia’s FL6 series is a lot closer to Optane in terms of performance and their implementation actually uses SCM-class NAND, though I’m hesitant about claiming that they really are using SLC.

Hello!

By “fast” I mean, snappy operations and speedy transfers, both in sequential & random read/write transfers.

Hello!

I am not trying to get the best “bang for buck”, I just want the best, period.

This is excellent question that nobody has dug into, since its both obscure and challenging to answer. May even be practically impossible to answer.

Trivial answer is “QLC run as pSLC” is SLC in the end performance wise. Its how controller programs nand flash in the end that determines final performance and endurance characteristics of the product. Nand flash is agnostic, it just stores charge level and its up to controler what charge level means what.

Direct comparison would however be possible only if you could reprogram same pair of controller and NAND flash in different modes and run tests separately for SLC, MLC , TLC and QLC mode.

No end tester has that kind of access to finalized product, it might be possible on early engineering samples that no one has access to.

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The best for boot drive? High end consumer optane or enterprise grade optane.

Their performance will not be eclipsed for years to come.

For general use Solidigm D7-P5810 and similar drives, but they will not universally best, no drive is. If money is no object or better, someone else is paying, I would take it over any high end consumer drive.

Both extreme overspend though economically speaking. But you cannot get modern SLC drive anywhere outside enterprise segment, where 5k USD is peanut change.

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No offense, but when the difference between the best and the bang for buck option is less than ten percent performance wise, it is stupid to go for the technically superior option - unless your use case really requires it.

It is like paying $20 per gallon for the 5% more fuel efficient biodiesel when the $10 per gallon regular diesel works just fine. All things being equal the former is of course better but not worth the premium. For most people.

If you want to burn money though either of the options listed are fine, after all it is your money :slightly_smiling_face:

Yeah.

I agree.

Yeah.

I agree.

I do get your point.
And, it’s not like I have a money printing machine at home.
I get it!

But here’s the thing:
While some computer parts become better & better by each generation (CPU, GPU, RAM, Coolers, etc.), SSD NAND gets worse by each decade!

I am using 2-bit MLC NAND drives now.
Going to a 3-bit TLC NAND is a downgrade!
The fact that we can go from PCIe 3.0 to 5.0, doesn’t mean that much.

Sequential speeds are what vendors advertize, without showing how pathetic those random speeds are, of their new shiny drive!
That’s why, people are saying that going from Gen3 to Gen5 didn’t have the impact that they were expecting.

I’ve been there. In short, this is currently an impossible goal.

Assuming you want non-volatile as well (which rules out DRAM), the remaining options on the market don’t get you high sequential throughput, high random IOps, and low latency. It used to exist in the PCIe 4.0 generation (as Optane P5800X), but then came PCIe 5.0 SSDs. :slightly_smiling_face:

Unfortunately, there will never be a PCIe 5.0 Optane, and NAND will not catch up to Optane’s low latency in the foreseeable future. You cannot cheat the lack of sequential performance by putting PCIe 4.0 Optane into a RAID-0 array as RAIDing Optane neutralizes its latency advantage. Thus, an iron triangle has materialized once again and your only recourse is to take Intel private and use your position as its new owner to make PCIe 5.0 Optane.

If “fast enough” sequential is fine, go with Optane. My second choice after that would be Kioxia’s FL6 series as I lean closer to random I/O more than sequential.

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No it isnt, only in the autistic/very theoretical sense where every parameter must be equal or superior, else i am getting ripped off. TLC weakpoints have been masterfully counterbalanced by smart controller design.

Modern TLC and some QLC drives are overall superior product compared to older MLC based products in all charactics including price, except:

  • DPWD , which is non issue for consumer sector
    • double so given much larger drive sizes vs old mlc drives
  • performance stability after pSLC exhaustion, which is also non issue in consumer sector if drive is sized correctly and not overfull
    • on modern large size drive pSLC cache area can be larger than entire mlc drive of yesteryear. And usually larger than most consumer working sets, so perf drop is not noticed.

Both price per GB and and price/perf have massively improved in last 10 years since MLC → TLC/QLC migration.

I still have my intel 320 somewhere around here and that thing expensive slow shit compared to even samsung 850 evo drive. And thats 10 year old sata tlc drive, left in the dust my modern nvme tlc drive designs.

Just avoid QLC drives unless you know what you are doing and do your research and you will be fine. And dont buy 50€ 2TB droves from aliexpress lol. Those guys are masochists.

MLC is not the savior you think it is, its old product that only exists in legacy and special applications. Pining for it in 2025 for consumer use is shooting yourself in the foot.

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I know about Kioxia’s FL6.
Those drives are using the U.3 connection.
Also, the price is… a leg and an arm.

Maybe the best thing would be getting a specialized software that turns TLC drives into SLC drives at the expense of losing 66% of its capacity.
(Such software does exist, and it can be downloaded from a russian dev site, as someone from TechPowerUp did it & created a YouTube video about it. However the procedure is risky!)
I wish the vendors of these SSD drives would offer this option in their official control panel software.

You’re right.
MLC is not the saviour.
But PCIe 5.0 1-bit/cell SLC would be amazing!
PCIe 5.0 Optane would be the best.

in the next week or 2 Samsung will be shipping the PM9E1 which will tank Gen 5 M.2 NVME drive prices.

The T705 2TB is substantially faster than the 4 TB

Now if you want actually fast, any general use enterprise U.2 will smoke any M.2 in random iops and better thermals.

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