Crucial M500 960GB review

Welcome to the clash of the terabytes as we see how the Crucial M500 960GB stands up against Samsung's 840 EVO. Earlier this year, we gave the M500 480GB 4.5 out of 5 for its combination of competitive performance and price/GB metrics, and this - the first of the terabyte class drives - only increases the value proposition.

In the coming years - or, given how fast the SSD market moves these days, the coming months - the M500 960GB might well come to be seen as a line in the sand. This was the first truly affordable, truly high-capacity 2.5-inch SSD available for a price that wasn't going to tear your wallet asunder.

Well OK, it still has an eye-watering price tag, but given how expensive solid state drives were even a year ago, it's an impressively low price point. Yes, it still has a long way to go to catch up with the good old spinning mechanical disk drive, but at least it's heading in the right direction.

The reason Crucial can offer such a large capacity disk at the price point they are asking is solely down to the NAND it uses. Up until now, the densest NAND found in SSDs has been of the 64Gb (8GB) variety. Crucial - or rather its parent company, Micron - has been able to double this, making the M500 series the first to use 128Gb (16GB) 2-bit 20nm MLC dies.

Moving to a larger die enables a decrease in the number of chips needed to reach a given capacity. This lowers the manufacturing cost of the drives, while simultaneously making them bigger.

Under the hood

At the heart of the drive is a Marvell 9187 eight NAND channel controller. Both it and the custom Crucial firmware are updates of the 9174 controller/firmware used in the previous generation M4 drives.

The updated firmware supports the latest ONFI (Open NAND Flash Interface) 3.0 standard. That brings with it power saving features and, more importantly from a performance point of view, an increase in the interface speed to 400MB/s (double that of the previous 2.0 standard).

Each NAND package in the M500 is made up of four of those 16GB dies, with the total capacity then made up of 16 64GB NAND chips (eight per side of the PCB). Joining the NAND on one side of the board is its Marvell memory controller and a 512MB DDR3-1600 cache chip, while on the other side of the board there's a matching 512MB RAM chip to make up the total cache.

Although the drive's true capacity is actually 1,024GB, Micron has used the proprietary RAIN (Redundant Array of Independent NAND) technology from its enterprise drives. This is essentially its version of over-provisioning, and looks to take care of any failed NAND and increase reliability. However, this does eat up some of the drive's overall capacity, hence the 960GB label.

Crucial has added a decent number of other features to the M500 series, all of which are more likely to be found in the enterprise space. Apart from the previously-mentioned RAIN technology, the drives have their own built-in power backups. That means if the power should fail, or some other gremlin gets in the system, resulting in a BSOD, the drive will finish any writing duties as long as the data is in the NAND.

The drives also feature proper thermal controls; if the drive goes above 70°C, it will throttle back by around 40% until it returns to a stable working temperature. The neat trick is that it does this in a manner that's invisible to the OS - very clever indeed.

Quick off the mark

As with the 480GB drive, Crucial quotes sequential read speeds for the 960GB drive of up to 500MB/s, while the sequential write speed is quoted at 400MB/s. Both of these turned out to be a tad conservative when compared with the results of the ATTO benchmark - 541MB/s for sequential reads and 454MB/s for writes.

Because the drive uses a Marvell controller rather than the ancient SandForce one, there isn't a significant difference in performance when it comes to data compression. This is neatly demonstrated by the AS SSD sequential benchmark results: in the incompressible data mode, the drive gave read/write scores of 496MB/s and 440MB/s respectively.

Synthetic benchmark scores are all well and good, but what about real life performance? Installing Microsoft Office took a mere five minutes, and copying a 50GB folder of mixed file sizes and types took four and a half minutes. Copying a 4GB image took a fairly brisk 20 seconds, and the drive took 83 seconds to copy a 17GB Blu-ray image.

Benchmarks

Sequential read performance
AS SSD: Megabytes per second: Bigger is better
CRUCIAL M500 960GB: 496
2x CRUCIAL M500 960GB RAID 0: 979
SAMSUNG 840 EVO 1TB: 515
CRUCIAL M500 480GB: 488
KINGSPEC MC1S81M1T: 2,122

Sequential write performance
AS SSD: Megabytes per second: Bigger is better
CRUCIAL M500 960GB: 440
2x CRUCIAL M500 960GB RAID 0: 842
SAMSUNG 840 EVO 1TB: 503
CRUCIAL M500 480GB: 408
KINGSPEC MC1S81M1T: 988

4K random read performance
AS SSD: Megabytes per second: Bigger is better
CRUCIAL M500 960GB: 62
2x CRUCIAL M500 960GB RAID 0: 71
SAMSUNG 840 EVO 1TB: 110
CRUCIAL M500 480GB: 60
KINGSPEC MC1S81M1T: 58

4K random write performance
AS SSD: Megabytes per second: Bigger is better
CRUCIAL M500 960GB: 23
2x CRUCIAL M500 960GB RAID 0: 23
SAMSUNG 840 EVO 1TB: 42
CRUCIAL M500 480GB: 23
KINGSPEC MC1S81M1T: 29

So, we're now hitting the sort of capacities we've seen from PCIe drives, but how close can we get in performance terms? We had two 960GB M500s, so it seemed rude not to build them into a RAID array to see if we could get any performance boost from pairing them up.

Verdict

Unsurprisingly, RAID 0 gives a nice bump in the headline sequential read/write scores. The reads jumped from 496MB/s up to 979MB/s, while the writes rose from 440MB/s to 842MB/s. When it came to dealing with the small bitty files of everyday use though, the RAID array hardly made any impact on the 4K read/write performance - and that's arguably where you want the speed boost.

And that's where the new Samsung 840 EVO 1TB drive is able to stand out. That drive may be slightly pricier if you want a drive that's terabyte class, but it beats this Crucial drive where it counts: in performance terms.

The M500 doesn't need any TurboWrite-esque shenanigans to maintain its performance, but in this class of drive it's still difficult to look past the superior Samsung.