Patriot Warp v2 128GB SSD Review

Stutter Issue Explained

What is the so called “Stutter Issue” that we hear so much about these days and what causes it? At its most basic, the stutter issue is intermittent pauses which lock up your system even when the system is not under a heavy load. For anyone who has never experienced this issue the easiest way to describe it is this: Insert a blank DVD into you DVD drive. If you are running Windows, your system (no matter how powerful) will pause until the optical drive is able to recognize the disk and respond to commands sent to it by your motherboards ATA controller. Basically, this is very similar to what happens when your SSD's onboard I/O controller becomes saturated and is unable to receive additional commands from the main motherboard controller. As soon as a backlog on your ATA controller happens, you system will become unresponsive for any where from a second or two, to ten or more seconds (depending on how long the “perfect storm” lasts).


Contrary to popular belief this can and does occur with spindle based hard drives as well, though it only happens with low performance models. A good example is this reviewer’s dual core laptop with 4GB of RAM and Vista Premium. From time to time Vista’s indexing service would saturate the bus and the slow 5400rpm Seagate drive would thrash for generally 10-20 seconds. A few tweaks are all it took to correct this issue; and the same is generally true of SSDs. Though, the faster and more powerful the SSD the lower the likelihood these pauses will be noticeable.

The biggest reason for this issue is MS operating systems were tweaked and enhanced to minimize latency, read and write issues associated with spindle-based drives. To achieve this, other areas of performance had to be compromised. Unfortunately, SSDs already have great latencies and do not write or read in a necessarily linear fashion; in fact their strengths and weakness do not overlap in any way with the more typical spindle drive for which the OSes have had decades of tweaking and experience to build upon. Windows 7 is rumored to be SSD friendly but until it ships (and is proven to do so) we will have to live with these quirks.


Some SSDS are more affected than others and it is mainly an MLC problem. Multi-Level Cell NAND chips do not have the typical 1 and 0 state; but in fact have 4 states. Since they have four states, they can effectively hold 2bits of information per cell. This allows for much denser NAND chips, but does so at the expense of latency. In order to write to a given cell, a write or erase cycle has to first be accomplished; then and only then, can a second cycle (the actual write cycle) take place.

On the surface this does not sound like such a big issue but further complicating things is the fact that this cell -when being erased or written to- cannot be read from. Also, on first blush this does not seem like such a big deal as the cycles are measured in mere nanoseconds, but a modern operating system can have numerous threads all reading and writing to (and from) the drive, and that’s even before you start to even use the computer. A stutter occurs when a “perfect storm” of numerous reads and writes are called for and the amazing performance abilities of the SSD are just not enough to handle the load.


While the style of NAND used is important, the actual I/O controller used can also play a large role in the drives characteristics. The JMicron controllers have received a bad rap as the earlier I/O controllers were, needless to say, ineffective and prone to severe stuttering. The newer 602 series of controller is much improved but still is not a perfect solution. Certain companies such as Intel have taken the stance “once bitten twice shy” and have distanced themselves from JMicron by the simple expedient of removing the JMicron controller from their SSD’s and using a different manufacturer’s I/O controller, backed by onboard Cache.

It may not be fair, but in the fast paced world of IT, second chances are rare and third chances are non existent. The interesting thing about these non Samsung reference design SSDs is the onboard cache is not used as it would be in a regular drive; rather it is just there to accept and store commands sent to the drive by the ATA controller (i.e. keep your motherboards ATA controller happy and lock-up free even if the SSDs I/O controller is overloaded). In the case of the Warp v2, Patriot has elected to stick with the JM602 controller and use no onboard cache; it certainly will be interesting to see how much improved the JM602 is and if this controller totally does away with the stuttering seen on past drives.