i-RAM as a Paging Drive

One question that we've seen a lot is whether or not the i-RAM can be used to store your pagefile. Since the i-RAM behaves just like a regular hard drive, Windows has no problem using it to store your pagefile, so the "can you" part of that question is easily answered. The real question happens to be, "should you?"

We have heard arguments on both sides of the fence; some say that Windows inefficiently handles memory and inevitably pages to disk even when you have memory to spare, while others say that you'd be stupid to put your pagefile on an i-RAM rather than just add more memory to your system. So, which is it?

Unfortunately, this is the type of thing that's difficult to benchmark, but it is the type of thing that's pretty easy to explain if you just sit down and use the product. We set up a machine, very similar to how we would a personal system, but tended to focus on memory hogs - web pages with lots of Flash, Photoshop, etc. Of course, we opened them all up at once, switched between the applications, used them independently, simultaneously, basically whatever we could do to stress the system as it normally would be stressed.

At the same time, we monitored a number of things going on - mainly the size of the pagefile, the amount of system memory used, the frequency of disk accesses, pagefile usage per process... basically everything we could get our hands on through perfmon to give us an idea if Windows was swapping to disk or not.

The end result? There was no real tangible performance difference between putting more memory in the system and using the hard disk for the pagefile or putting less memory in the system and using the i-RAM for the pagefile. Granted, if we had a way of measuring the overall performance, it would have shown that we would be much better off with more memory in the system (it runs faster, and it is accessed much quicker than off the i-RAM).

The only benefit that we found to using the i-RAM to store our pagefile was if you happened to have a couple GBs of older DDR200 memory lying around; that memory would be useless as your main system memory in a modern machine, but it'd make a lot better of a pagefile than a mechanical hard disk.

One more situation we encountered that would benefit from storing your pagefile on the i-RAM was those seemingly random times when Windows swaps to disk for no reason. But for the most part, our system was slower when we had less memory and stored the swapfile in it than when we had more memory and less swap file.

Adobe Photoshop is a slightly different creature as it keeps a scratch disk that is separate from the Windows pagefile. We tested Photoshop and used the i-RAM as our scratch disk, but in all cases it always made more sense to just throw more memory at Photoshop to improve performance where we ran out of memory. If the operations you're performing in Photoshop can fit into system memory, then you'll never touch the scratch disk.

Overall, based on our testing, the i-RAM doesn't make much sense as a paging drive unless you have the spare memory. The problem with "spare" DDR200 memory is that it is most likely in small 64MB, 128MB or maybe 256MB sizes, which doesn't buy you much space on an i-RAM drive. For most people, you're much better off just tossing more memory in your system.

i-RAM Pure I/O Performance i-RAM as a boot drive
Comments Locked

133 Comments

View All Comments

  • mattsaccount - Monday, July 25, 2005 - link

    This thing would still be useful as a pagefile in some circumstances--if all your memory slots were full and/or you had extra memory lying around. This is what I had been planning to do with it (currently have 4x512mb, plus a couple other smaller capacity DDR sticks which would be nice to use b/c for photoshop stuff). But the price is too high. I'll wait till it drops.
  • Son of a N00b - Monday, July 25, 2005 - link

    I would love to get two of them and run them in RAID-5 possibly...that way you also have a back up...

  • Gatak - Monday, July 25, 2005 - link

    You'd need minimum 3 cards/disks for RAID-5.

    However, using this card as a journaling device for a normal filesystem, like ReiserFS or Reiser4 might be very beneficial. Wouldn't require much RAM either.
  • ukDave - Monday, July 25, 2005 - link

    Extra things that could have been covered were:

    Would there be a difference with other SATA cards, such as 3Ware etc - i.e. would CPU usage make a difference perhaps?
    Why not use SATA-IO (SATA-2) instead of the older and slower SATA (re: Gigabyte)?

    But otherwise a very informative article, thanks Anand.
  • ss284 - Monday, July 25, 2005 - link

    It would be best to wait for the second version of the card, which will hopefully have a cheaper IC as well as sata II support. Theres no doubt that the ram can do 3.0gb/s.

    Imagine what 2 of these in raid 0 would be like.


    -Steve
  • SDA - Monday, July 25, 2005 - link

    - File copy performance is mostly a moot point, because copying files from disk to disk will go as fast as the slower of the two can, and other applications that typically require disk performance (unarchiving et al) will only see a minimal performance increase due to bottlenecks in other parts of the system (which becomes even less valuable when you consider that you won't be doing a whole lot of unarchiving to a disk that small).

    - Gaming benefit would be okay if it you could fit more than about one modern game on it.

    - Using it as a pagefile is, as Anand noted, pointless.

    - It does improve boot times, but it's not a huge difference, how many of us shut down often enough to actually be bothered by a few seconds in boot?

    - It does improve app loading times slightly, but if you're opening and closing apps that take a lot to open and close, it's probably because you don't have enough system memory, so buy more memory instead.

    So basically: whoopee.
  • DerekWilson - Wednesday, July 27, 2005 - link

    I'm just gonna pick at a single point ... you could install one game to the i-ram at a time and then archive them on another drive.

    You get fast zip times on i-ram and a single file transfer to a magnetic disk is faster than multiple small files (moving the the archive won't take long). Just unzip the game you want to play to i-ram ...

    but then ... that kinda defeats the purpose doesn't it ...

    I could see this being fun to play with, but I have to agree with Anand -- it needs higher capacity before it is really useful.

    Plus, I'd like to see SATA-II :-)
  • miketheidiot - Monday, July 25, 2005 - link

    I don't really see anyone using this, its costs way too much for too little storage and too little performance benefit, not to mention the risk of data loss. I'll give it a look again when they get some higher bandwidth flash or something like that. this i can pass on for now.
  • Sea Shadow - Monday, July 25, 2005 - link

    I dunno, I could see the extreme enthusiasts getting these. I mean after all, if they have the money to buy a system with SLI 7800 GTX and FX 57 this would be pocket change.
  • BoberFett - Monday, July 25, 2005 - link

    I'd imagine that in some areas the CPU is still the bottleneck and for others the 150MB/sec limit of SATA may be.

Log in

Don't have an account? Sign up now