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w6kd

SSDs and alignment

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I hadn't seen this mentioned here yet...I just discovered that my Vista boot SSD (an Intel X-25M G2) was not properly formatted with the blocks aligned with the sector boundaries. Fixing that resulted in a hefty 17% improvement in the benchmark scores and a noticeably snappier OS drive.Theoretically, the Vista installer is supposed to create the boot sector aligned with a 4K sector boundary, but in my case the upgrade version apparently inherited the old NTFS partition boundary. When the SSD isn't aligned, the 4K block reads/writes cross sector boundaries, and so to read/write a standard 4K block of data, you have to read/write two 4K blocks to get it all, slowing things down. Win 7 is supposed to be better at installing itself aligned (although I suppose an upgrade from XP could still be a problem), and anyone using XP with an SSD needs to check this because most XP installs apparently don't respect the sector boundaries.There's a decent free benchmark utility called "AS SSD" that checks the boundary alignment--it'll show a green "OK" or a red "BAD" in the upper left corner of the window when running against a drive. Or you can use DISKPART...select the drive, then list the partitions and the offset data will be displayed (needs to be evenly divisible by 4K). The standard offset in Vista/W7 is 1024 or 2048, but anything evenly divisible by 4K should work with most, if not all SSDs.Lining things back up, if the boundary offset is off, is a simple matter of copying the drive contents to a backup, and reformatting the drive using DISKPART (use command "create partition primary align=1024"). Once the data is restored, make sure to use a utility to restore the VolumeID of the drive so that some of the more common copy-protection scemes don't get triggered on the new partiton. Realigning the partition is a b*tch-kitty on a boot partition, though. I finally succeeded by using a linux-based CD utility called GPartEd to shift the lower edge of the partition to the 2048MB boundary offset. Windows will not let a boot partition's boundaries be changed while it's running, so you need a utility that boots on a removeable drive (ie CD/DVD/USB) to BartPE/WinPE etc outside of the disk's OS to change a boot sector boundary. The Acronis True Image backup I was using just restores a backup to the original faulty alignment...supposedly some of the newer backup programs allow realignment, but I have no personal experience with any that do.RegardsBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

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Bob, you can change the system partition boundaries with EASEUS Partition Master for example. It's a free windows based app and very easy to use.The trick with Acronis is to avoid recovering the whole disk, as that will clone everything, including the format and partition offsets. If you format the SSD in Windows so that the partition is alligned, and then clone the C:/ partition (or whatever the letter) Acronis will keep the allignment. Then just make another partition for the System Reserved one after the "C:" partition and clone that. Finally move the MBR to the SSD and you're good to go.http://forum.avsim.n...607-hdd-to-ssd/

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Bob, you can change the system partition boundaries with EASEUS Partition Master for example. It's a free windows based app and very easy to use.The trick with Acronis is to avoid recovering the whole disk, as that will clone everything, including the format and partition offsets. If you format the SSD in Windows so that the partition is alligned, and then clone the C:/ partition (or whatever the letter) Acronis will keep the allignment. Then just make another partition for the System Reserved one after the "C:" partition and clone that. Finally move the MBR to the SSD and you're good to go.http://forum.avsim.n...607-hdd-to-ssd/
I tried cloning it and I couldn't get the disk to boot. I'll check out that utility...I was sorely disappointed by Acronis' performance in this little "event."At any rate, I have things lined up, and made a new backup of the properly-aligned SSD.CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

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