OCZ Agility 3 SSD review - Specifications and architecture

The SSD NAND FLASH partitions

So the storage unit we'll be testing today is a 240GB version. Here's how that works. OCZ places a NAND flash partition of 16 ICs onto one PCB. The NAND FLASH partition the new SandForce 2281 assigned, opposed to the 2582 Controller used in the PRO assigned for multi-channel IO.

Main controller differences, the regular Agility and Vertex do not have some enterprise features like power loss data protection & data recovery protection, that 2500 series also offers 28% over-provisioning for optimal drive endurance and data protection & management hence the PRO version has less available storage space. Now there's a 20% IOPS perf increase over the last generation product for the Vertex 3 but 30% for the PRO.

No, the biggest difference in-between the regular Agility 3 / Vertex 3 and the Vertex 3 PRO is the fact that the PRO makes use of Enterprise-Class MLC NAND Flash, yes .. better NAND MCL Flash memory. As such it got a MTBF of 10 million hours (!) and the regular Vertex 3 will get the new (cost effective) 25nm NAND Flash memory with a lesser lifespan set at an MTBF of 2 Million hours.

So what about 25nm NAND lifespan ?

Personally I'm not at all a excited about the new 25nm NAND FLASH memories, the overall lifespan of the ICs has been reduced from 10.000 towards 5,000 program/erase cycles. Rumors are that the numbers for consumer grade 25nm NAND flash memory (as used on the SSD tested today) are even lower at 3000 program/erase cycles.

But granted, as drastic as that sounds, it's all relative as this lifespan will very likely last longer than any mechanical HDD. Drive wearing protection will help you out greatly. With a normal filled SSD and very heavy writing/usage of say 10GB data each day 365 days a year you'd be looking at roughly 22 full SSD write cycles per year, out of the 3000 (worst case scenario) available. However, all calculations on this matter debatable as usage differs and even things like how much free space you leave on your SSD can effect the drive.

Anyway back to the SSD.

SandForce, opposed to other controllers, enforces a trick as they can write to the FLASH memory less then the competition needs to by using real time compression. The SF controllers store a representation of your data and not the actual data itself. It does that by using a partition of the available NAND flash memory. This is why on SandForce based drives you do not see an extra memory cache chip, which in fact saves on the bill of materials used for the SSDs.

Now we mentioned it already, but the SF-2281 series controller will support up to roughly 500MB/s sequential read and write speeds, that's 62.5MB/s per one of the available eight channels. Combined the bandwidth is just exceptional for single non RAID drive.

OCZ merges one SandForce 2281 controller into the product and by the way, SF-2281 controllers support TRIM. Deduct a few GB per partition for real-time data compression and then you have your SSD ready. But all that data needs to travel over an interface ... of course.

OCZ Technology Agility 3 PCB with 16 Micron NAND flash memory ICs (8 on each side).