OCZ RevoDrive 3 X2 review

Memory (DDR4/DDR5) and Storage (SSD/NVMe) 367 Page 3 of 16 Published by

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The SSD NAND FLASH partitions

 

The SSD NAND FLASH partitions

So the storage unit we'll be testing today is a 480 GB version. Here's how that works. OCZ places four NAND flash partition of 16 ICs onto two PCBs. The NAND FLASH partitions all get one new SandForce 2281 assigned for some massive multi-channel IO. The RevoDrive 3 series uses asynchronous Micron MLC NAND (25nm) memory by the way.

So what about 25nm NAND lifespan ?

I've been saying this over and over again, personally I'm not a fan of 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 are debatable as usage differs and even things like how much free space you leave on your SSD can effect the drive.

OCZ RevoDrive X2

SandForce, opposed to other controllers, enforces a trick as they can write to the FLASH memory less than 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.

The trick though is that the four controllers on the RevoDrive 3 X2 are pointed towards that proprietary OCZ RAID controller, here two partitions are configured as RAID0, done twice ... effectively doubling up performance per array.

OCZ RevoDrive X2

So that's roughly what you need to know about the NAND memory and SandForce controllers. Let's move onwards to that RAID unit, as it comes with a new VCA 2.0 software layer that adds some pretty snazzy features.

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