OCZ IBIS SSD review

Specifications and architecture

Hey dude, welcome to page two. Here's where we'll look a little deeper inside the actual product. The OCZ IBIS is, as stated, an SSD based on MLC NAND flash memory.

It's more advanced then just an SSD that you plug into a SATA port though. The first thing you'll notice is that this storage unit is big in size, 3.5" actually. Internally, several SSDs are RAID'ed and interface wise, it uses a new proprietary High Speed Serial link which we'll explain later.

The end result here is that you'll get a SSD storage unit with a massive IO performance peaking up-to 740 MB/sec in read performance and a scorching 720 MB/sec write performance.

Now always bare in mind that a manufacturers loves to show you the burst peak performance, not average. Regardless of that fact, which we'll show you in the benchmark sessions, the IBIS is revolting fast.

The OCZ IBIS is a 3.5" SSD that is available in several volume sizes: 100, 160, 240, 360, 480, 720 and even a 960GB are available. The products range from 450 EUR towards a near irreverence 2500 EUR, in USD that's slightly more expensive. OCZ covers the unit with a 3 year warranty.

To understand the product we'll need to realize that there are three primary technologies embedded into the IBIS. As such we'll continue the technology coverage in three stages:

1. The SSD partitions paired with Sandforce controllers
2. The Silicon Image RAID controller
3. The HSDL interface

We'll explain each one in a simple manner.

The SSD NAND FLASH partitions

So the IBIS we'll be testing today is a 240GB version. Here's how that works. OCZ places two NAND flash partitions onto one PCB. Each 64GB partition will get a SandForce 1200 based IC assigned for multi-channel IO. OCZ now inserts two of these NAND units into the IBIS. That means accumulated four SandForce 1200 controller have a total of four 64GB partitions. Deduct a few GB per partition for real-time data compression (SandForce controllers require this) and then you have your SSD partitions ready. The two Sandforce controllers now lead towards a RAID controller.

The RAID controller

Controlling the two SandForce ICs is a Sil RAID controller, model 3124 SoftRaid 5. It actually is the same one used on the 1st generation OCZ RevoDrive. It will assign four active SATA II channels, one to each of the "SSD partitions" controlled per controller.

The partitions will be then setup in RAID0 (Stripe) effectively quadrupling performance, in theory that is. As all that data requires a decent chunk of bandwidth to operate in. So the next step is to tie the RAID controller to a fast interface as clearly SATA2 will not cover it any longer. And sure, we are still puzzled as to why a Sata 6G controller was not implemented at this stage. But...

The HSDL interface

With so much performance thrown at the interface towards your PC, SATA2 certainly is not going to cut it. In fact even SATA3 or SATA 6G as you might call it would be insufficient, yet expect some latency issues with so much going on inside that controller.

OCZ therefore decided to go for the unusual and from RAID controller up-to your 4x PCIe interface (add-on card) The OCZ IBIS SSD utilizes a proprietary serial interface that the company has branded as "HSDL" for High Speed Data Link.

It all sounds extremely complicated, but it's far more simple than you think. For the bigger part, PCI Express is the center where HSDL is to be found really as it's four PCIe links combined together, yes... the one single HSDL channel consists of four PCIe lanes tied together, like a band of brothers. One x4 PCI Express 2.0 slot serves up 2000 MB/s and as such the HSDL link offers up to 20Gb/sec peak bandwidth and does that with standard SAS connectors. Simplicity at its best really.

So in theory this technology is over three times faster when compared to the latest 6Gbps SATA technology. This will give the RAID unit enough breathing space to move its data in.

The HSDL link at the SSD connects to a small add-on card that seats on a PCIe x4 connector. The card has a bridge chip on its end which is then connected to the motherboard chipset via x4 lanes of PCIe 1.0. That provides as much as 1 GB/s of bandwidth of throughput with the help of a Pericom PCI Express Bridge, the PI7C9X130 making the PCIe 4x link happen.

The typical usage in this configuration is to “bridge” legacy 64-bit PCI products to PCI Express systems. That's really all there is to it... anyway let's head into a photo-shoot covering all the ins and outs.