The TRIM Conundrum & Marvell's Answer



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To get the absolute best long term performance out of a Solid State Drive your system has to be able to pass on the TRIM command. This is because most modern SSD controller designs are built and designed upon the assumption that the a system will be able to provide TRIM commands to the drive’s controller.For the ATA TRIM command to occur there are many different components which need to work hand in hand for the TRIM command to be sent and received by the SSD controller. The primary lynchpin here is the operating system. If you are running an older OS (pre Windows 7) the operating system itself will not know how to send the TRIM command. In addition, the motherboard’s storage controller itself must be able to process the TRIM command. AMD motherboards which predate the 800-series chipsets and Intel products using a pre-ICH9R setup simply don’t support TRIM regardless of the OS being run. Further complicating things is the prerequisite that the onboard controller be working in AHCI mode as IDE isn’t supported nor can the SSD be part of RAID array. With the exception of some exotic, factory RAID’ed Solid State drives (such as the Revo 3) RAID + SSD means no trim support.The last crucial link is the drivers which also need to support TRIM and currently Microsoft AHCI, Intel RST or AMD’s latest versions all work well. The easiest way to relate to all of these requirements is to think of each one as a link in a chain: if any one is broken your solid state drive will not receive TRIM commands and could degrade very quickly.The introduction of TRIM really did have an impact upon the perceived longevity of SSDs but there are still many consumers who don’t posses systems capable of passing on the command. Unfortunately, most SSD controller manufacturers design their chips based on the assumption that TRIM will always be a possibility. This means in order to get the best possible long term performance out of a modern SSD, you’ll need a TRIM-supporting system which could mean a costly upgrade to go along with that brand new SSD.So what about all those consumers who don’t have TRIM capabilities? Before TRIM was implemented, controller designers created routines to minimize and alleviate performance degradation. These self-maintenance routines go by many names but are usually called “Idle Time” or “Background” Garbage collection.This “old school” solution is of course the somewhat perfect answer for non-TRIM environments. Sadly, not all algorithms and routines are created equal and efficiency varies greatly from one controller maker to another. Since SandForce expects people to have TRIM capable systems, their self maintenance routines are very mild a best and thus very slow. So slow in fact that without TRIM, even the mighty SF2281 based drives can see their performance degraded very quickly. In extreme cases pauses and stuttering can even occur.While SandForce and others went the route of assuming their customers had TRIM, Marvell did not. In fact, Marvell seems to have actively focused upon and have designed their controller for consumers who want a large performance boost but don’t want to upgrade their entire system to get it. This is why Marvell controllers – especially this second gen “9174” - have more aggressive self-maintenance routines which start working sooner and faster than their competitors. The high performance, high efficiency self-maintenance routines within the Performance 3 really are the secret weapon in its arsenal but as we will see later in this review, they can act as a double edged sword as well.