sandiks extreme ssd only 150 MB/s write speed

[Bokaj7331]

Hi,
Ive got the following build:

Intel Core i5 3570K

Gigabyte Z77N-WIFI

8GB Corsair
1600Mhz DDR3

Corsair 650TX Modular
Intel HD 4000

SanDisk Extreme
SATA 6Gb/s
120GB SSD

Seagate Barracuda
SATA 6Gb/s
1TB HDD

and I only get around 150 MB/s write speed on my sandisk extreme ssd on mountain lion 10.8.2.

I activated TRIM via TRIM-Enabler.

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Has anyone the same problem?

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[goldjungee]

SATA 3 Cable?

AHCI - Mode in BIOS?

Right Port (SATA3) on the Board choosen?

 

[Bokaj7331]

yes

 

[DBP]

That doesn't sound terrible. In fact it is borne out by some online reviews of the drive. Sure my SanDisk Extreme 240 GB gets ~250 MB/s with incompressible data, but I wouldn't be surprised if the 120 GB model was a touch slower.
Remember, BlackMagic Disk Speed Test is designed to test the speed using video data (BlackMagic make cameras) so it generates random data which the drive can't compress. If you were to write easily-compressed data such as zeros I think you'd find the speed goes up closer to 500 MB/s.

For example (in Terminal):

dd bs=128k count=16384 if=/dev/zero of=YOUR_FILENAME_HERE

will write a 2 GB zero-filled file, and at the same time in another Terminal window:

/usr/sbin/iostat -d -w 2 -n 99

will give a report every 2 seconds of how much traffic is going to/from each drive on the system. You can watch iostat while running BM Disk Speed Test too.

 

[melvyn]

I get write speeds of 128MB/s and read of 413MB/s on a Sandisk Extreme 120GB. Is this normal?

 

[nobodynose]

I get write speeds of 128MB/s and read of 413MB/s on a Sandisk Extreme 120GB. Is this normal?

I'm getting almost double the write speed on a Sandisk Extreme 240GB (about 243MB/s). My read is about the same.

 

[melvyn]

Do you have any advice as to how I might improve my write speeds?