OCZ Z-Drive m84 PCI-Express SSD Review

Article Index

The Bottom Line, Sort of...

Performance Summary:
To say our results with the OCZ Z-Drive were a mixed bag would be an understatement.  Early on in our testing, we literally got the notion that we needed to "look" for ways to demonstrate the product's strength.  Too many times under synthetic benchmark testing, the Z-Drive fell flat, but there were also test conditions that showed big gains for the product, as was seen in our ATTO larger file transfer tests and CrystalDiskMark tests.  One thing is for certain, small file random operations are not a strength for the product, but clearly large file transactions, especially write transaction are its strength.  These results had us digging deeper with respect to demonstrating real-world test conditions for the Z-Drive where it would excel and also where it wouldn't.  As we garnered from our custom large file transfer tests, the Z-Drive was handily up to the task.  And as we showed you in our Left 4 Dead game level load tests, the Z-Drive shows mostly competitive performance on par with only a single standard SATA SSD.

To be completely frank (or Ralph or Harry for that matter), when we consider the sum of its parts, we expected more from the Z-Drive.  What we're looking at here is an SSD RAID card with a full-fledged RAID processor on board along with dedicated cache memory, all talking over a PCI Express X8 link with a ton of bandwidth at its disposal.  We expected the product to put up a fight with the likes of at least an SSD RAID solution driven by a software RAID controller over a motherboard's integrated Southbridge.  That, however, simply wasn't the case under many everyday test conditions we looked at, save for large file transfers.  In reality, to us, the Z-Drive feels a little less than fully baked.  We have seen similar oddities with hardware RAID controllers on the market, in conjunction with SSDs in RAID 0, so perhaps that points to the primary issue. 

We haven't explored other RAID modes much, but it appears that at least some of the RAID controllers on the market today aren't optimized all that well for SSDs and are apparently still tuned to hide the latencies of standard spinning hard disks, when they really need to be tuned to take advantage of the exponentially lower latency response and access times of the average SSD.  Perhaps with some time and a few BIOS revisions, OCZ can get together with LSI and improve the product's performance for more mainstream tasks. 

That said, we feel that currently, the Z-Drive is best suited for a few key niche' applications and usage models only.  If you're the type of end user that needs to drive large file write and read operations, as would be the case for a digital video production for example, then the OCZ Z-Drive m84 256GB model we tested would serve you well.  In addition, if you consider the cost per GB of the product, versus competitive SSDs on the market, the Z-Drive drops in with a moderate price premium over a single 256GB SATA SSD, on the order of about 20 - 25%.  However, you'll still need to consider the reliability aspects of a SSD RAID solution even with OCZ's 1 million hr MTBF specification and standard 3 year warranty.  When all is said and done, we think the Z-Drive is an interesting product that partially exploits current technologies available in the market, but perhaps needs a bit more maturation time in the oven in order to appeal to the enthusiast, power user or mainstream user.


  • Fast large file reads and writes
  • Low CPU utilization, hardware RAID
  • Elegant single slot PCI Express design
  • Reasonable cost per GB considering RAID controller and memory


  • Barely as fast as single SSD for small file read/write performance, boot drive and application loading
  • Still high cost per GB relative to similar sized SSDs on the market
  • Requires external power source
  • Mechanical restrictions on some motherboards

Related content