Stereodude
Not really a
Here's why you can't trust ATTO on a RAID controller or disk with a very large cache. The 256MB data length is just too small to get accurate results. Here's 5 back to back runs with ATTO v2.41 on my 6 x Samsung 5400RPM 1.5TB RAID-5 array on a Dell Perc 5/i with 256MB of cache.
First you can see they're not all that consistent run to run. Second if we compare them to an Iometer run set up to mimic ATTO's testing but with a much larger data length we don't see a whole lot of agreement. In the slowest test shown below (.5K read) IOmeter read ~7.36GB of data taking the cache out of play.
![attopass1.png](http://img83.imageshack.us/img83/7915/attopass1.png)
![attopass2.png](http://img83.imageshack.us/img83/3585/attopass2.png)
![attopass3.png](http://img377.imageshack.us/img377/9246/attopass3.png)
![attopass4.png](http://img133.imageshack.us/img133/5755/attopass4.png)
![attopass5.png](http://img180.imageshack.us/img180/6356/attopass5.png)
First you can see they're not all that consistent run to run. Second if we compare them to an Iometer run set up to mimic ATTO's testing but with a much larger data length we don't see a whole lot of agreement. In the slowest test shown below (.5K read) IOmeter read ~7.36GB of data taking the cache out of play.
![iometersa.png](http://img190.imageshack.us/img190/128/iometersa.png)