Sunday, September 26, 2010

Moving the Windows pagefile to flash/SSD drives - revisited...

It's been about a year and a half since I first started playing with moving a portion of the Microsoft Windows operating system to solid-state devices like Compact Flash cards and DOM Flash drives. My goal was twofold: to check the reliability of the solid-state drives, and to see if I could realize a boost in Windows perfomance compared to the spinning platter alternatives.

There were concerns at the time that Flash memory had a limited lifespan, and couldn't really handle repeated read/write cycles over time. I had no idea how much of a problem that would be during a long term test, but I was willing to sacrifice an Industrial CF card and Flash DOM drive to the cause, regardless.

To be honest, the Windows XP pagefile really doesn't hit things too hard. That could be attributed to the fact that I run dual hyperthreaded Xeon processors (4 logical processors in the Task Manager), and never had less than 2Gb of RAM in any of the test machines, with a total of 3.5Gb in one of them. With that much memory and parallel processing power, Windows XP Pro probably didn't need to access the pagefile as much as it could have with fewer resources available.

I said earlier I used Industrial Compact Flash - there's a reason for that. I learned that not all Compact Flash is created equally. If you want to use a Compact Flash card as a real hard drive, it has to be compatible with the IDE or SATA bus of a computer's motherboard. Using an IDE-to-CF adapter card, I discovered that some CF cards are UDMA compatible, most are not. The ONLY way to guarantee hard drive compatibility in the CF card world is to purchase Industrial Compact Flash, which is specifically designed for hard drive replacement use in embedded systems. While this guarantees they can be used as IDE hard drives, something tells me they may also be rated for heavier use in read/write cycles, too. That may be cheating with respect to my long term test, but looking for compatible CF cards via hit-or-miss purchasing didn't sound too appealing, either.

So how did they work? Pretty well, actually. Neither the CF card nor the Flash DOM module gave up the ghost, and were used every day for that year and a half. Under Windows XP Pro SP3, I was not able to format either in NTFS, but was able to use them formatted in FAT32 - so I left them in that configuration. I did not defragment them, nor did I set Windows to flush the pagefile during shutdown. I let Windows manage the pagefile size automatically, and was never in danger of running out of space on either the 4Gb CF card, or 8Gb Flash DOM module. I did use the HDDLED utility to show when the pagefiles were being accessed, and noted the greatest usage was during boot-up and when minimizing open applications. There were sporadic flashes of activity throughout a Windows session, but the majority of pagefile hits came from the instances I mentioned.

Applications like Adobe Creative Suite 3, Quark Passport, Microsoft Office 2007, and IE/Firefox browsers opened noticeably more quickly, with Adobe really standing out as a benefactor. Fragmentation of the main system hard drive sans the pagefile was also reduced, which is to be expected.

What I managed to accomplish was prevent the system hard drive from moving the read/write head all over the disk platter trying to concurrently access both a running application and the Windows pagefile. I also freed up several GB of hard drive space by moving the pagefile to the separate flash device on a different IDE channel. The system hard drive endured less fragmentation, and the pagefile took advantage of the excellent random access read characteristics inherent to solid-state devices. I can understand why both Microsoft and Intel recommend using these devices for such a purpose now.

I've since taken the concept just a wee bit further, by obtaining another IBM workstation, and outfitting it with a more recent version of the earlier flash drives, a purpose-built 8GB SSD drive built by Transcend. This was installed into an IBM Intellistation Z-Pro workstation, with 2 hyperthreaded 3.2Ghz Xeon processors, and 4Gb memory. Windows 7 Professional 32-Bit was installed, and this time, I was able to format the SSD drive using NTFS. Here's the drive box:

Here's the drive installed into the IBM's hard drive cage:

These are a bit faster in the read/write access times, per the manufacturer's data sheet. Moving the Windows 7 pagefile to the SSD was just as easy as doing so in Windows XP, and poses no real difficulty in setup. Windows 7 really likes this configuration, and that also comes as no surprise, since Windows 7 uses ReadyBoost for other solid-state media. (I tried ReadyBoost, and saw no performance increases, probably because of the 4Gb memory) This configuration is only about 5 months old, so I will keep an eye on it over time to see how well it holds up over time.

In the meantime, if you can find CF cards, Flash DOM modules, or smaller SSD drives at a good price, I can wholeheartedly recommend this technique. As SSD technology improves, I can hardly wait to see what the future holds in store!

1 comment:

Doug said...

Thanks for the update. Time to start looking for iCF cards!