3rd Party SSD

SH1987 wrote:

Should it matter that I have turned it on after I installed osx?

Nope, and how are you supposed to run the program with no OS X installed? 😁

SH1987 wrote:

...Can anyone advice if my drive will work ok or not with what I have done or will I need to boot from my external drive and erase my ssd then turn trim on somehow then clone with my external drive again...

Is SanDisk Tech Support absolutely positively 100% clear that you're using a Mac with OS X? I'm no expert on this but I believe TRIM is tied to ACHI (Advanced Host Controller Interface and Serial ATA drives) but not IDE (which refers to Parallel ATA). I believe which to use for your HD could be specified in your PC's BIOS and it had to be correct before TRIM could work. If I'm right, SanDisk Tech Support was giving you the generic answer they give to PC users.

TRIM Enabler should get the job done. Just be aware that you may have to re-enable TRIM whenever you do an OS update or upgrade.

As you know, SSD's don't operate quite the way HD's do. In order to overwrite a page of data, the page has to be erased first (HD's just write to the page again). But SSD's can't erase just the page; the whole block of data the page is in has to be erased too, and other pages in the block are still valid, so the whole thing (except for the page to be overwritten) has to be moved to a different block before the current block is erased.

On the other hand, if a page is simply deleted, it's left alone and gets included in that move before block erasure even though it's no longer valid. That will continue until the OS issues an instruction to write to that page again. Since writing to an SSD shortens its life, unnecessary writes are not good, especially given the hoops an SSD has to jump through to write anything.

TRIM notifies the SSD that the deleted page space is available now rather than waiting for an explicit "use the page again" instruction. As such, it's an ongoing process, and while having TRIM enabled from the beginning is a good idea, it's likely it'll touch most of the pages eventually because, given the limited life of individual cells on an SSD, wear-leveling will spread cell usage around to smooth wear, even outside the partition, as garbage-collection progresses.

Or, to put it another way, I don't think you need to erase your SSD and start over. Indeed, given that lots of writing can shorten the useful life of an SSD, erasing it and cloning your HD's contents all over again is just wearing all those cells out faster.

SH1987 wrote:

Thanks for the info so would you leave trim on or off? i wont bother with the erase and clone again even if sandisk come back and say it should be done at the start I pretty much turned it on as soon as i started using the drive it was only off during the clone I dont know how sandisk can say you can turn it on with no os installed but im going to see what there reply is. I have read about having trim on or off and it seems drive with a sandforce contoller dont need it as back ground garbage takes care of it and OWC drives suggest leaving it off. My drive is this :http://www.sandisk.com/products/ssd/sata/standard/?capacity=128GB in my reply to sandisk I have asked if this one had a sandforce controller im thinking not...

If the controller is not a SandForce and SanDisk says using TRIM is OK, I'd enable TRIM and just keep it running that way. I use a SandForce SSD and also looked into TRIM usage, including the OWC position. At least back when I was checking, their link to discussion of that question went back quite a ways and there was a time when TRIM did not play well with SandForce firmware. That has since been fixed, but this link is more recent and still advises against it. There is also the question of how SandForce actually stores your data - the controller uses a sophisticated form of compression and decompression on the fly so there may be some inconsistency between the LBA (logical block address) where the OS thinks your data is and where the SSD controller actually put it.

So if SanDisk has given TRIM its blessing, just turn it on and enjoy the improved speed and reduced wear that should result. As to that performance, note that SanDisk says (up to) so you know YMWV. The actual write speed could be affected by how full the drive is and how much behind garbage collection is. That's something that TRIM is designed to address.

SH1987 wrote:

...So would you recommend trim or not I am currently running trim enabler system seem to run great but ssd only been installed for less than a week...

I've got to say that SanDisk's response is fascinating. First, they confirm both that your SSD has a SandForce controller and that it's compatible with TRIM. Second the links they supply recommend the TRIM enabler that you're using even though it needs an OS installed first for it to run in. Just to confuse things further, I believe essentially all current SSD's have garbage collection of some sort, which conflicts with advice for using TRIM in the first link (that kind of advice could make your head hurt). At least as I understand it, TRIM is an adjunct to GC because it deals with deleted files immediately that GC won't until the space they occupy is directly overwritten by the OS giving a command to write to that particular LBA.

So, to answer your question, if it was me, I'd use TRIM Enabler to turn TRIM on. Since System Info already says TRIM is supported, I'd be happy and then just leave it alone to do its thing. However, I wouldn't follow the first link's advise to erase free space, just to be safe. GC and TRIM will get there soon enough.

SH1987 wrote:

...Please be advised these links are NOT SanDisk resources and we take no responsibility for them...

Thanks for posting that.

They'll supply you with the link as a form of support but won't agree with what the link says. I think I detect an "Ooops."😉