Win7 64bit and solid state hard drives

[ronpeck]

Hi!..I am looking to build a new PC and will include a Corsair SSD.. need some information re TRIM support..Win7 I understand supports TRIM but do you need to install a program or is this already in Win7?
Thanks
ronpeck

 

[clifford_cooley]

Thrax wrote an article

What is ATA TRIM?

An SSD’s total size is composed of thousands of smaller units called “blocks,” which average about 512k these days. SSDs deliberately try to spread written data across all of these blocks so as not to prematurely wear out the memory chips, which can only accept a limited number of writes. This technique is called wear leveling. Over time, wear leveling guarantees that every block on the SSD will become filled with a hodgepodge of active and deleted data. Once this happens, new writes force the drive to perform an intensive process called the read/erase/modify/write cycle.

An REMW cycle forces an SSD to scan its blocks for deleted files, copy active data to cache, purge the deleted files, append the new data to the data in cache, and then write the cache back to the new free space. This is called write amplification, and in serious cases, it can force an SSD to shuffle up to 20GB of data just to write 1GB of new information. This causes significant performance issues for SSDs.

The solution to this problem is to let SSDs physically erase files the moment they are deleted in the OS, and that is precisely what the TRIM command does. Windows 7 is the only Microsoft OS that supports it, and it must be used with a TRIM-compatible drive.

Read more here - http://icrontic.com/news/crucial-updates-m225-ssds-for-ata-trim

My interpretation was that the SSD's does the trim function when performing the "REMW(read/erase/modify/write) cycle"

 

[Thrax]

When Windows deletes a file, it doesn't actually remove that file from the hard disk. Instead, it leaves the file on the drive and merely updates its index of files to say "this space is now free." That's no big deal for mechanical hard drives, but it's a huge deal for SSDs which depend on having free space for optimal performance.

SSDs use free space to shuffle data around to accept new data written by the user. But if the drive is junked up with files that have been deleted, but not removed by Windows, the physical storage on the drive gets filled up very quickly. If Windows can't move data around within the NAND cells, it has to make a messy sequence of reads and writes in system RAM that eventually get copied back to the SSD as a completed blob of data. This process of flushing the deleted files, working on the new data in RAM/cache, and writing it all back is very slow compared to what gets done when the drive has free space to work with.

Long story short: If the drive has TRIM, the drive's performance will stay consistent throughout its lifetime, rather than slowly degrading to terrible levels as the drive's memory fills with files you've deleted, but Windows hasn't.

 

[ronpeck]

Thanks all.. I had a handle on most of that but was unsure how Win7 and the drive went about using the TRIM..Auto or via a seperate program but you are saying that the SSD has the ablity to do this on it's own volition.? (Clifford ..re TRIM support SSD's you can add Corsair X128 & X256)

 

[Veedaz]

Just to but in

Windows 7 by default sets DisableDeleteNotify = 0, meaning it is always sending the TRIM command to the storage stack, but not all SSDs are TRIM enabled.

 

[clifford_cooley]

Windows 7 by default sets DisableDeleteNotify = 0, meaning it is always sending the TRIM command to the storage stack, but not all SSDs are TRIM enabled.

If this is true then Trim is controlled by Windows 7

 

[Thrax]

The TRIM command is part of the ATA spec. The ATA spec defines how hard drives connect to the machine, how they communicate to the system and the OS, etc. So, Windows 7 controls the TRIM feature, but the SSD has to be able to understand the command it's receiving, which is why drives need to be upgraded with TRIM support.

Note that some drives can never be updated for TRIM because they simply don't have the right cotnroller tech.

 

[ronpeck]

Hi! Thanks all for your replys..lots of information..a bit more to you all ..Yeh only some are TRIM compliant so far but more are comming on line all the time..Australian Mag. APC Dec. gives a benchmarks on some SSD's (128g) best under their test was Intel 128g but not then with TRIM...saw an article since where Intel have issued a firmware upgrade to give TRIM support but then they have withdrawn it because of troubles with Win7!!

 

[Thrax]

The firmware issues with the Intel X25-M G2 drives were fixed 2 weeks ago. There was an issue with the flashing tool they provided to perform the update.

 

[catilley1092]

You mean that when you delete a file or program, it's not really deleted? I don't get this, because I use CCleaner to delete files (including temp internet files) every day. I overwrite the info 35 times (the Guttman method). There must be something that I'm missing here.

 

[clifford_cooley]

You mean that when you delete a file or program, it's not really deleted? I don't get this, because I use CCleaner to delete files (including temp internet files) every day. I overwrite the info 35 times (the Guttman method). There must be something that I'm missing here.

This is only for SSD(Solid State Drive) not the standard drives with platter's. SSD's are all electronics and does not have moving parts.

This is my interpretation - Long story short, a function used to make the SSD's live longer had a side affect and need a new function called Trim to operate correctly.

 

[Thrax]

It doesn't matter what kind of hard drive it is. Windows doesn't physically remove the file when you tell the PC to delete it. It just updates the master file table to indicate that those clusters of space are free for writing again. If you store new information on that spot, the old data is overwritten. This is why data recovery works when the partition is broken, because the files are still physically stored on the disk.

 

[ronpeck]

Bit of info. for all and thanks for all your replys...Just installed a Corsair X256 SSD w/- TRIM ..works great, boot time was 105seconds now 40sec.