Final Words

The Toshiba OCZ RD400 is aimed at the very top segment of the consumer SSD market where the primary goal is to get the highest possible performance. The suggested retail prices aren't quite top of the line, which signals that performance expectations should be a bit lower than "the fastest that money can buy" but it needs to be in the ballpark. With the current state of the market, being a "mid-range" PCIe SSD can still mean being the second fastest drive available.

The RD400 only sets a few performance records but elsewhere it at stays close to the PCIe SSD competition and is much faster than any SATA drive. The once formidable Intel SSD 750 can now only top the charts on one benchmark and is simply too expensive for today's market, but it does retain the distinction of being the sole 2.5" U.2 SSD for the consumer market. Against the Samsung 950 Pro, the RD400 of the same capacity is usually slower, but the difference would be hard to feel during interactive use.

Looking outside the direct Samsung comparisons, the 1TB RD400 provides a capacity that Samsung doesn't yet offer, but it comes at a premium and the increased capacity doesn't provide much of a performance increase over the 512GB model. The 128GB RD400 on the other hand is smaller than any 950 Pro and thus competes mainly against grey market OEM Samsung SM951s that don't come with the nice 5-year warranty that Toshiba offers.

On the other hand, comparing the RD400 against SATA SSDs is tricky. At first glance, it may seem straightforward that a drive with two to three times the performance on most benchmarks is a good deal for a mere 30-50% price increase. But increased SSD performance brings diminishing returns for real-world use. PCIe SSDs are not yet mainstream products and are not a good value for consumers who aren't very sure that they will benefit noticeably from faster storage. Upgrading from a mechanical hard drive to a SSD alleviates a major performance bottleneck but the experience of moving from SATA SSDs to PCIe SSDs is not as revolutionary. I suspect most consumers would be better served with a larger SSD of moderate performance than a cramped but blazing fast PCIe drive, but for those who have the means and a need, the RD400 is a flagship halo product that unquestionably satisfies its purpose.

High-End SSD Price Comparison
Drive 960GB-
1.2TB
400GB-
512GB
240GB-
256GB
120GB-
128GB
OCZ RD400A (AIC) $759.99 $329.99 $189.99 $129.99
OCZ RD400 (M.2 only) $739.99 $309.99 $169.99 $109.99
Samsung 950 Pro   $316.99 $178.00  
Samsung 850 Pro $416.87 $219.21 $126.99 $90.60
Intel SSD 750 $1199.99 $349.99    
SanDisk Extreme Pro $340.60 $183.00 $104.99  
Samsung 850 EVO $319.99 $149.99 $88.39 $66.80

The RD400 does have some downsides other than not being the absolute fastest drive on the market. Our testing showed it to be significantly more power-hungry than the Samsung 950 Pro, which suggests it may be less suitable for laptop use. The higher power consumption is likely due to a combination of a less efficient controller and NAND that needs more power, but we don't have enough information to pin down the primary cause.

Overall the high power consumption in the small M.2 package also makes heat a somewhat greater concern. Like the Samsung 950 Pro, the RD400 strikes a precarious balance of performance against temperature. During our most intensive tests the OCZ SSD utility put up several alerts that thermal throttling had been engaged due to the drive's temperature. The temperature never got close to the critical level where damage to the drive is possible, but performance was negatively affected. Another round of testing is underway with the RD400s in our usual PCIe to M.2 adapter to investigate how the drive is affected by less effective cooling and how its power consumption differs when fed a direct 3.3V supply instead of using OCZ's adapter to convert 12V down to 3.3V. I suspect these tests will probably show that the RD400 is still inferior to the Samsung 950 Pro for laptop use.

Overall the Toshiba OCZ RD400 earns its place as a high-end SSD. It delivers great performance all around with no major weaknesses and is a solid competitor to the Samsung 950 Pro. It is roughly the second-fastest client SSD on the market and with pricing that promises to undercut the 950 Pro it should be a great value and a very welcome source of competitive pressure.

ATTO, AS-SSD & Idle Power Consumption
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  • tarqsharq - Wednesday, May 25, 2016 - link

    Interesting article as always. I had been hoping for a larger price gap between this and the Samsung 950 Pro. At current prices, I think the choice is fairly obvious unless you need a 1TB SSD. Reply
  • Chaitanya - Wednesday, May 25, 2016 - link

    You have a choice of Sandisk X400 as well if you want 1TB capacity in M.2 form factor. Reply
  • edzieba - Wednesday, May 25, 2016 - link

    There's also the OEM version of the OCZ drive, the Toshiba XG3, which is also available in a 1TB m.2 SKU. Reply
  • Lord of the Bored - Thursday, May 26, 2016 - link

    And who DOESN'T need a 1TB SSD? Reply
  • MrSpadge - Friday, May 27, 2016 - link

    I think you're mixing up "want" and "need". Reply
  • DanNeely - Wednesday, May 25, 2016 - link

    "Unlike most cheap adapter cards, the RD400's adapter draws power from the PCIe slot's 12V supply and converts it to the 3.3V required by the M.2 drive."

    PCIe slots provide 10W of 3.3V power directly. (I believe this was originally done to make converting legacy cards via a bridge chip easier.) Why would the card need to do any DC-DC conversion?
    Reply
  • Byrn - Wednesday, May 25, 2016 - link

    I'd assume that if they convert they can get cleaner 3.3V than if they use the feed through the PCIe slot, or that they can design in better resilience to sudden power demand changes...

    Basically, by converting I would have thought they can better fit the power supplied to the drive to the demands it makes.
    Reply
  • digitalgriffin - Wednesday, May 25, 2016 - link

    You can filter any volt feed with enough capacitors. But you lose power efficiency when you do. Reply
  • Alexvrb - Wednesday, May 25, 2016 - link

    Yeah but they're filtering the power either way so converting from 12V -> 3.3V is less efficient than using 3.3V to start with. But getting back to what Byrn was saying... Byrn, they don't have a choice: This drive draws too much power to use the 3.3V supply.

    Look at idle power figures in this article. ~2.5W @ 12V. At 3.3V that would already be pushing it (right around 9W already). Under a load it's going to draw too much. So they had to use the 12V rail.
    Reply
  • Wardrop - Wednesday, May 25, 2016 - link

    2.5 watts is 2.5 watts. If it's a higher voltage, it's less amps, and vice versa. I think you've confused watts with amps? Reply

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