Momentus XT, Momentus, Momentus Thin, MobileMax, and other notebook drives

[buckygeo]

Can anyone confirm if Momentus XT improves the performance when swapping (or thrashing)?

I have a MacBook Pro (Core Duo) that cannot accept more than 2GB of RAM (only Core 2 Duo's can take more RAM).

I believe an SSD drive would effectively offer 'limitless RAM" (subject to performance of the BUS), but I am unsure how Seagates "Adaptive Memory technology" handles SWAP operations by either OSX or Windows.

Does anyone have experience with this?

Thanks!!!

[WiseDrive]

This one is a hard one to call.

AFAIK, there is some caching of the swap file in the SSD portion, but, whether it will drastically improve performance, it is an open question.

The limitations of an old machine, and old SATA bus, and many other things come into question.

To say "limitless" memory is stretching the point a bit.. as many other factors... including the efficiency of the page file subsystem, and also the inherent limitations of addressing of the OS etc. come into place.

[Klok]

Hey,

Is the swap an actual partition in Mac OS ? I remember reading that one could make a system more "alert" using the swap in an aggressive way. But most people using SSD are afraid of the write limit and therefor disable it when possible.

From what i understand, the MXT will cache data according to usage pattern, and most probably cache only certain lba. In order to be sure that your swap is always cached, you would have to use the partition(lba range) in a specific way. I'm really not sure how one could make that since we don't have access to the Algorithm and since 10 read of a file will probably cache it. There is an ATA8-ACS draft that suggest a command for hybrid hard drive to pin a certain lba range. I'm not sure this has been implemented in the MXT but it might worth to look.

Good Luck,

Klok

[buckygeo]

I have received two private messages from a moderator, who ?possibly? works for Seagate.

For everyones benefit I post this information.

"The XT drive will improve boot time and increase the speed of programs that are started shortly after boot, otherwise it will perform like a normal drive.

and

"The flash acts as intermediary for sector access to reduce seek time from the physical disk. The seek time and bootup time are increased. That iswhat we have observed with the increase in performance."

Looking at the various suggestions (thanks to all) it seems to me that the RAM attached to the Momentus XT is behind the dirve controller, is used to optimise I/O, and that OSX wouldn't be able to directly access it so as to enhance SWAP. The other option is RAMDISK but that is a whole new "can of worms".

Thanks! 

[WiseDrive]

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buckygeo wrote:

Looking at the various suggestions (thanks to all) it seems to me that the RAM attached to the Momentus XT is behind the dirve controller, is used to optimise I/O, and that OSX wouldn't be able to directly access it so as to enhance SWAP. The other option is RAMDISK but that is a whole new "can of worms".

Thanks! 

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There are two different memories we are talking about.

The FLASH (NAND, SLC) cache directly improves READ performance for data chosen to be cached by the firmware.

There are rumors of write caching being done on the Flash cache in a future firmware release.

The DRAM cache is an entirely different story.

As I understand it, it is used to improve write speed.