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High access time 2x Agility 3 (120gb) in RAID 0

post #1 of 4
Thread Starter 
Hi all,
My computer is taking a huge amount of time to turn on (1 minute) with 2x SSDs in RAID 0. This prompted me to run HD Tune in which I found my access time was 1.3ms...WAY above what it should be (although I doubt this would make the startup time so high). Any ideas? Can answer questions as I'm aware there's not much that can be diagnosed from this one screenshot.



Thanks

Edit: FWIW, Task Manager in Windows 8 was saying I had an average response time for the hard drive as over 2,000ms while I was running an error scan in HD Tune, but has gone down to between 1 and 80ms while idling...
Edited by samywamy10 - 4/18/13 at 4:48am
 
Dell XPS M1330
(13 items)
 
 
CPUGraphicsRAMHard Drive
Core 2 Duo T9300 @ 2.5ghz GeForce 8400M GS 4GB Intel X-25M 80gb 
Optical DriveOSMonitor
Replaced with 200gb 7200rpm Windows 7 Home Premium 64bit 3x HP 2311f 
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Dell XPS M1330
(13 items)
 
 
CPUGraphicsRAMHard Drive
Core 2 Duo T9300 @ 2.5ghz GeForce 8400M GS 4GB Intel X-25M 80gb 
Optical DriveOSMonitor
Replaced with 200gb 7200rpm Windows 7 Home Premium 64bit 3x HP 2311f 
  hide details  
Reply
post #2 of 4
Um.....are you using a 3.0 SATA III (or 2) port on your motherboard that has a Sata III cable (Or 2) connected to it , and your SSD?
post #3 of 4
Post a screen of AS SSD?
post #4 of 4
I/O consistency and latency (IOCL) is becoming a new area of performance testing for consumer SSDs, and has been an important aspect of enterprise SSD performance for much longer.

Your HDTune results are a basic example of IOCL performance, notice how the yellow points that indicate access times are not a single flat line or cluster of points over a small range. A single line or tight cluster of points indicates little change in access time. You can see three fairly consistent lines of points, running from left to right, in the graph, the main one at the bottom, which is ~1ms or less, which is good. The second line is at ~5ms, and the third ~10ms, with clearly visible points above and below the second and third lines.

The 1.6ms access time result is likely an average, but as can be seen, the variations in access time cause the average transfer rate to be half the maximum transfer rate. Note that where the high peaks in transfer rates are located, you don't see many yellow points above the first/lowest yellow line of points.

IOCL performance is measured with different workloads. Task Manager was checking the I/O latency while your HDTune error scan was running, no doubt reading and writing while testing, the worst case workload. We don't know how much, but the result you had were seemingly bad, but your result is likely more common than we realize. This type of testing is not easy to understand, so has been passed over in SSD reviews. A recent review/comparison of three SSDs that incluced the current king of SSDs, as nominated by most members of this forum, when tested for IOCL performance, was easily beaten by another SSD not held in such high regard. But then, the test results are not that easily evaluated into one clear winner and loser, as we seem to want so much. Reality is not that simple.

How to fix this? That is not easy, or even necessarily possible. The main factor for better IOCL performance is spare area on the SSD, the more OP space, the better. That's why enterprise SSDs have up to 50% of the user space matched with OP space. TRIM and time for GC to work are other factors. How much space is free on that RAID volume?
Edited by parsec - 4/18/13 at 11:06pm
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