Momentus XT Issue-Please Help

I recently installed a 500gb Momentus XT hybrid drive in my MBP. I have noticed improvements in loading of applications and in bootup time. However, when I recently ran Xbench it gave me these results for the disk test portion.

Disk Test 49.48
Sequential 113.92
Uncached Write 126.54 77.70 MB/sec 4K blocks
Uncached Write 162.33 91.85 MB/sec 256K blocks
Uncached Read 64.15 18.78 MB/sec 4K blocks
Uncached Read 183.06 92.00 MB/sec 256K blocks
Random 31.61
Uncached Write 9.37 0.99 MB/sec 4K blocks
Uncached Write 274.42 87.85 MB/sec 256K blocks
Uncached Read 99.44 0.70 MB/sec 4K blocks
Uncached Read 163.72 30.38 MB/sec 256K blocks

All of the tests using 4k blocks are giving bad results. Does anyone know whether this is software or hardware related? Any tips on how to fix this. In addition, I recently installed 8gb of ram in the computer, but I made sure not to knock the SATA connector. Thanks for the help.

4k blocks give issues to even SSD's under random r/w speeds.

I understood that when I bought the drive, but still, the performance is 10x worse than it was with the stock 250gb drive. Any suggestions for fixing this or could it be a defective drive? The larger block r/w are good, so I don't think it is defective, but I'm open to opinions.

You have a drive that requires multiple boots and numerous uses out of apps so that it can learn how you use your drive. Also, speeds fluctuate A LOT. The advertised speeds aren't read/write speeds that you see 100% of the time, they are just peek speeds, which are similar to an ssd showing 275mb/s but only 60-100mb/s random speeds.


1 thing. Did you restore a the OS or did you put a fresh one on? If you had a fragmented drive previous to restoration, your new drive will be just as fragmented, or possibly worse with new caching.

I cloned my old drive w/CCC to the XT in an external enclosure. I have had the drive installed for several months, I only recently ran the xbench test. After seeing the results I ran Techtool and Disk Utility and found that the volume structure was corrupt. I booted from the Mac OS X install DVD and successfully repaired the drive. However, I am still getting disappointing Xbench results. Would it be a good idea to format and reinstall OS X from my Time Machine backup? Or should I just ignore the results and not worry about them? As I said, it is not noticeable in everyday use. In addition, does anyone know of any other performance test software I could use. When I checked on the Xbench website other MBP users w/ a XT installed had awful 4k r/w block scores. Perhaps it is simply a problem between XBench's methods and the Momentus XT.

I did the test with all my hd's and my OCZ ssd. The only one that was faster was the OWC ssd. The stock 250gb that came with my mbp had the slowest times(5400rpm). The other stock hd's running at 7krpm had relatively faster read/write times than the 250gb, but were slower than the XT.

The only thing I can think of is that maybe you have a lot of misplaced files causing slow test results.

When I first installed my XT, I needed some of the programs and documents asap the way I left them, so I backed everything up. After I was done with that though, I did a fresh install. I got full start-up to the desktop in 29-33 seconds(completely loaded). With the 250gb, it was around 49 seconds. The OWC ssd starts up in 19-21 seconds consistently.

Do you get bootup times around 30 seconds with it?

Personally great believer in registered SuperDUper for backups, but when cloning a drive use Disk Utility's own, and free, Restore program. Go into Disk Utility and hit the restore key. Simply select the drive to be copied, and the target drive and away you go. Perfect every time.

Moderator chscag and I have discussed previously problems of cloning a boot drive to a new drive. Do a search of the threads.