Vertex 3 performance issues

Your results seems just fine 411 score is amazing.

xbench is quite an old bench and doesn't reach close to the performance the drive can do. Differences from run to run is also normal.

Here is my older Vertex Turbo.

Disk Test 277.52
Sequential 270.37
Uncached Write 392.72 241.13 MB/sec [4K blocks]
Uncached Write 246.06 139.22 MB/sec [256K blocks]
Uncached Read 171.42 50.17 MB/sec [4K blocks]
Uncached Read 425.45 213.83 MB/sec [256K blocks]
Random 285.05
Uncached Write 95.12 10.07 MB/sec [4K blocks]
Uncached Write 443.64 142.03 MB/sec [256K blocks]
Uncached Read 3905.19 27.67 MB/sec [4K blocks]
Uncached Read 990.48 183.79 MB/sec [256K blocks]

Benchmarks from http://www.guru3d.com/article/ocz-vertex-turbo-ssd-review-test/7 clearly states that the drive should be 260/245 mb/sec at sequential 256k blocks, but xbench maxes at 213/184 mb/sec

If you compare to my Western Digital Black 2TB 7200rpm, which is considered a fast desktop hard drive, this old Vertex Turbo crushes it:

Disk Test 118.85
Sequential 213.14
Uncached Write 245.46 150.71 MB/sec [4K blocks]
Uncached Write 172.50 97.60 MB/sec [256K blocks]
Uncached Read 183.68 53.75 MB/sec [4K blocks]
Uncached Read 289.72 145.61 MB/sec [256K blocks]
Random 82.40
Uncached Write 26.84 2.84 MB/sec [4K blocks]
Uncached Write 561.24 179.67 MB/sec [256K blocks]
Uncached Read 169.57 1.20 MB/sec [4K blocks]
Uncached Read 276.94 51.39 MB/sec [256K blocks]

Also compare your scores with anandtech here.
He tested your SSD along side many others. I think your numbers are just great.

http://www.anandtech.com/show/4205/the-macbook-pro-review-13-and-15-inch-2011-brings-sandy-bridge/7

Keep in mind, you have the 120GB version, and Anand tested the 240GB, the 240GB is a bit faster, due to more chips.

 

Here's the most relevant performance metric of them all in a non-realworld benchmark like this one. Linear reads and writes - while often producing some really high and impressive figures - isn't how most apps do disk I/O. Particularly when several apps do I/O all at once - such as when booting up and logging in for example.

That's when an SSD will bring the greatest benefit, not when reading or writing really large single files.

 

Try using 'Disk Speed Test' from the App store. Post what the results are from that bench.

 

my vertex 3 max oops does
(xbench on mac; atto on win 7)

seq read avg: 498 mb/s
seq write avg:486 mb/s

I believe very few have achieved the ocz advertised speeds of 550 random read/write!