Gigabyte's i-RAM: Affordable Solid State Storage
by Anand Lal Shimpi on July 25, 2005 3:50 PM EST- Posted in
- Storage
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.
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simpletech - Tuesday, July 26, 2005 - link
I think another possible use (besides certain kinds of servers, like mail servers), is for video capture. The size is a bit small, but if you were capturing segments of footage, it might work. And the price could be reasonable.BikeDude - Tuesday, July 26, 2005 - link
"but 32-bit Windows can't use more than 4GB of RAM, including the swap file size."First of all... "Swap file" is a misnomer. We talked about "swap file" back in the Windows 3.1 days when the OS would swap a process' entire memory space to the *swap* file.
These days the OS will read/write selected pages of a process' memory from/to the cache manager (who may or may not elect to use the disk to get to the physical pagefile). *Paging*, not "swapping". Executables and libraries are memory mapped and thus start their lives with all pages firmly on disk (so a big executable won't necessarily load slow, but many small DLLs OTOH just might).
I don't have Windows XP in front of me, but my 32-bit Windows 2003 Standard ed. with 4GB memory and 1GB pagefile certainly doesn't seem affected by the limitation you mention. Enterprise edition can address even more physical memory... Each process is still limited to a 2GB virtual address space though. (32-bit processes marked capable of such will gain a 4GB virtual address space under 64-bit Windows)
I realise that XPSP2, despite PAE, is limited to 4GB physical memory (http://blogs.msdn.com/carmencr/archive/2004/08/06/...">http://blogs.msdn.com/carmencr/archive/2004/08/06/..., but pagefile as well? Nah, sounds iffy.
JarredWalton - Tuesday, July 26, 2005 - link
Without PAE (or something similar), 32-bit OSes are indeed limited to 4GB of RAM. This is what is being referred to, as PAE is limited to Intel and I don't believe it's available on non-Server versions of Windows. (Correct me if I'm wrong, but PAE is pretty much only on Xeons, right?)You're right that it's paging instead of swapping now, but there's really not much difference between the two. Basically, you put data onto the HDD in order to free up physical RAM, on the assumption that the least recently used data that was moved to the HDD won't be accessed again for a while.
JarredWalton - Tuesday, July 26, 2005 - link
Anyway, I've modified the comment to reflect the original intent. If you're running PAE and Server, it's a whole different ball game for high memory systems.Penth - Tuesday, July 26, 2005 - link
Wow, my friend and I talked about the possibilities for these things several times. But at 3x the initial price and not the performance increase I would have expected, the techie in me is disappointed. My wallet is happy though.StanleyBuchanan - Tuesday, July 26, 2005 - link
I wonder what the issue is with RAID that Anand comments on.... seems odd that it would behave differently than a HD in this respect and cause problems...I would love to have 12gb or more... which is enough for Windows XP, a productivity suite, and a modern game... anything more could be run from NAS
Zan Lynx - Sunday, July 31, 2005 - link
Probably something to do with the PCI bus power. Perhaps two of these cards take more juice than the bus expects to provide while on standby.phaxmohdem - Monday, July 25, 2005 - link
I saw someone else posting as well, but I would very much like to see some database performance numbers from this device, as well as perhaps a web-serving benchmark.xTYBALTx - Monday, July 25, 2005 - link
How some FPS benchies?GTMan - Monday, July 25, 2005 - link
I laughed when I saw that line :) A very interesting device and I look forward to where this goes in the future. Your "Final Words" could use a bit of brevity.