Sandisk Extreme 120GB- Super slow Write Speeds??

[shenaniganmod10]

Hi,

Just finished a 3770k Hackintosh/Cross Windows 8 machine for a friend of mine, built on a Z77X-UP5 TH along with a GTX 670 from Gigabyte. The OSX Boot drive is a Sandisk Extreme SSD in 120GB flavour.

I installed Blackmagic earlier, and did some speed testing. Was shocked when it came to results as no matter which directory I tried, read speeds stayed at around 400-450MB/s (looked about right), and never any more than 150MB/s Write. I so far I've updated the SSD Firmware to the lasted version, and made sure TRIM is properly enabled. Still the same problem.

The 840 Pros in my system give me 3-400MB/S in Blackmagic, so I'm wondering if this is at all normal for these drives? If not, I'd be hugely appreciative of any suggestions/ideas/fixes!

Thanks in advance



(PS: I've attached a screenshot of the Blackmagic Window)

 

[shenaniganmod10]

*Bump*
Any thoughts anyone?

 

[GeraldB]

It seems your SSD has a Sandforce Controller like OCW or Intel 520 drives. The Sandforce controller writes everything compressed and that means the real write speed is the around the double of your measurement. You could also test this drive with AJA Benchmark. That benchmark gives the real writes also for Sandforce drives. But also on my Hackintosh the AJA Benachmark tool does not work. It did work on my iMac late 2009 I had before.

 

[melvyn]

I also have the same problem. Does anyone have any ideas?

 

[steftrikia]

Right click on your hard drive, then show informations. Add your user account and specify "read and write permissions".
Then AJA benchmark should work...

 

[melvyn]

That technique for enabling AJA System Test on the OS drive doesn't work for me. I can't select my OS drive still.

My write speeds are around 128MB/s and read is 413MB/s in Blackmagicdesign. Is this normal? My 1TB storage hard disk gets around 184MB/s read and write.

 

[nobodynose]

That technique for enabling AJA System Test on the OS drive doesn't work for me. I can't select my OS drive still.

Another technique is to run AJA System Test as a privileged user. Go to a terminal window and type the following (you have to use backslashes to escape the spaces in the path):

cd /Applications/AJA\ System\ Test.app
cd Contents
cd MacOS
sudo ./AJA\ System\ Test

Enter your password and then you'll be able to select your boot drive to test on.

 

[melvyn]

Thanks nobodynose, I might give that a go. I've read that the blackmagic test uses incompressible data, which is why the Sandisk Extreme shows slow write speeds. As long as it's working as it should, and I'm getting the performance you would expect, I'm not too bothered.

 

[melvyn]

Also, how would you suggest wiring the SSD to the mobo, and do I need to install the 3rd party SATA drivers? What do they do exactly?