SATA3 SSD Write Speeds SLOW in Mountain Lion! Please Help!

[Ngiardina]

I'm wondering if anyone can help with this little annoyance. I just finished building the system listed below in my signature. Everything is working perfectly, with one little issue. I ran BlackMagic's Disk Speed Test, and I am getting 150MB/s write speeds! Read speeds fluctuate anywhere from 450-520MB/s, but writes never come above 150.

Some added information, I am using a cable that came with MB, and it is marked "6Gbps)" It is plugged in to "SATA3_2", which is the light colored connector on my board. I used EasyBeast with default settings on installation, third party sata kext is installed, ehci and xhci are enabled in BIOS.

I know this is going to be a simple fix, just hoping someone has some experince. I've searched and searched, but can't find a solution.

 

[Ngiardina]

Thelostswede had this to say about the issue:

There has been quite an outcry by some users here with regards to the performance of their SSDs in OS X, as they're not getting the performance they're expecting. Well, there are many reasons for this, but I'll try to cover some of the main issues that most people seem to experience. Please note that this isn't a complete guide and we're not offering any specific buying advice here, see it instead as guidance and spend some time doing your own research before taking the jump and buying your first SSD.

SandForce based SSD such as OCZ's Vertex 3, Corsair's GT, Sandisk's Extreme, use compression, this means that if you're working with incompressible data, i.e. video files or already compressed files, the performance will drop, drastically, as the SandForce chip can't compress the data. In other words, if you're using something like BlackMagicDesign's Disk Speed Test, you'll get pretty poor results. However, these SSDs are fast when it comes to compressible data, so if you've used something like CrystalDiskMark in Windows, you'll see very high performance numbers that should be close to that of the manufacturers claimed read and write speeds, as this data is compressible. One other issue with SandForce based SSDs is that the performance tends to degrade over time, by as much as 15-20 percent. The only way to restore a SandForce drive back to its original performance is to format it and start over. TRIM does help, but if you're hammering your SSD regularly, you will see a performance drop as even TRIM doesn't bring these drives back to their original, new state performance.

So it seems to be correct.

 

[pr3m-5ingh]

Thelostswede had this to say about the issue:

There has been quite an outcry by some users here with regards to the performance of their SSDs in OS X, as they're not getting the performance they're expecting. Well, there are many reasons for this, but I'll try to cover some of the main issues that most people seem to experience. Please note that this isn't a complete guide and we're not offering any specific buying advice here, see it instead as guidance and spend some time doing your own research before taking the jump and buying your first SSD.

SandForce based SSD such as OCZ's Vertex 3, Corsair's GT, Sandisk's Extreme, use compression, this means that if you're working with incompressible data, i.e. video files or already compressed files, the performance will drop, drastically, as the SandForce chip can't compress the data. In other words, if you're using something like BlackMagicDesign's Disk Speed Test, you'll get pretty poor results. However, these SSDs are fast when it comes to compressible data, so if you've used something like CrystalDiskMark in Windows, you'll see very high performance numbers that should be close to that of the manufacturers claimed read and write speeds, as this data is compressible. One other issue with SandForce based SSDs is that the performance tends to degrade over time, by as much as 15-20 percent. The only way to restore a SandForce drive back to its original performance is to format it and start over. TRIM does help, but if you're hammering your SSD regularly, you will see a performance drop as even TRIM doesn't bring these drives back to their original, new state performance.

So it seems to be correct.

Hey,

It seems like you know about SSDs. . .Could you help me on mine please? When I check my results I get between

Write: 127mb/s
Read: 182mb/s

Which seems VERY slow to me compared to the guy that started this thread. Could you tell me why I would be getting these results.

Thanks.

 

[Ngiardina]

Hey,

It seems like you know about SSDs. . .Could you help me on mine please? When I check my results I get between

Write: 127mb/s
Read: 182mb/s

Which seems VERY slow to me compared to the guy that started this thread. Could you tell me why I would be getting these results.

Thanks.

Your write speeds seem very much inline with what I get from my Vertex3, and seems inline with what to expect from any SandForce-based SSD. The only thought that comes to mind in regards to the read speed is that maybe the drive is attached to a SATAII header on the board. My board has (4)SATAIII AND (3) SATAII headers, and 2 of the SATAIII are Marvell gSATA, which netted even slower read speed. I would verify that you are attached to the Intel SATAIII headers and if not change it and retest.

 

[pr3m-5ingh]

Your write speeds seem very much inline with what I get from my Vertex3, and seems inline with what to expect from any SandForce-based SSD. The only thought that comes to mind in regards to the read speed is that maybe the drive is attached to a SATAII header on the board. My board has (4)SATAIII AND (3) SATAII headers, and 2 of the SATAIII are Marvell gSATA, which netted even slower read speed. I would verify that you are attached to the Intel SATAIII headers and if not change it and retest.

Thanks for the info. . .I just removed my other hard drive and cd drive and tried it in all the ports and did the test. I get the same result :S is there anything else I could check or do?

Also I noticed my boot time is about 34 seconds with my other hard drive connected(which only has documents, music & vidoes on) When this is removed my boot time goes down to about 9 seconds. Is there anyway of keeping it at 9 seconds with other drive still connected?

All info would be great. Thanks.

 

[Ngiardina]

Thanks for the info. . .I just removed my other hard drive and cd drive and tried it in all the ports and did the test. I get the same result :S is there anything else I could check or do?

Also I noticed my boot time is about 34 seconds with my other hard drive connected(which only has documents, music & vidoes on) When this is removed my boot time goes down to about 9 seconds. Is there anyway of keeping it at 9 seconds with other drive still connected?

All info would be great. Thanks.

Not sure, dude. Maybe disable all of the SATA ports that aren't in use and configure your BIOS to look for your SSD first and only. That is how I'm setup. Sorry I can't be more help.

 

[pr3m-5ingh]

Not sure, dude. Maybe disable all of the SATA ports that aren't in use and configure your BIOS to look for your SSD first and only. That is how I'm setup. Sorry I can't be more help.

Thanks for the info ill try and figure out how to do that lol