SSD Swap file question -- keep it all on one drive?

[TheFaz]

I was thinking of moving to a SSD for my gaming system, but this raises a question I have about performance.

With an SSD, is there any performance advantage to placing the swap file on a different disk?

My Windows XP configuration includes a 2 hard disks-- one for the OS and applications, the other with two partitions for swap and backups respectively.

M$ has always recommended putting the swap file on a different disk on a different disk controller, and barring that putting the swap on its own separate partition.

I can understand the disk getting congested when reading and writing data all at once, but with SSD we no longer have to worry about spinning plates.

Maybe the bus path can get full so it's better to have two drive. I'd be interested in hearing if anybody has run some benchmarking tests in this regard.

[Joe Average]

If you have a secondary physical drive, put the pagefile on it, definitely. This has two benefits:

1) It allows for better multitasking overall because the system/OS will be able to read and write at the same time as required - it can read/write from one drive and read/write with the other at the same time. With just one drive, you can only read or write at any given moment, so while modern hard drives are damned fast, they still can't do both at the same time.

2) You'll relieve a lot of small random writes on the SSD which is the Achilles Heel of modern SSD technology. Yes, they're getting faster all the time, that's a given, but still the biggest slowdown on SSD hardware is with small random writes. The page file is typically seen as one big file on the drive in terms of space required, but the OS is reading/writing 4KB chunks (a page of data) so, that's most definitely considered small random writes.

You can leave the page file on the SSD and add a secondary one to the physical hard drive, that works too, but if and when a random write needs to be done on the SSD itself, performance will suffer and you may end up having that "stutter" that a lot of people notice with SSD hardware.

If you have a lot of physical RAM and you're not actively using it (like 4GB and you rarely use more than 2GB or whatever), you could look into disabling the page file (setting it to 0 bytes) and go from there, or just resizing it to a smaller amount if that's not an option. Personally if it were my machine, and I have 2GB or more of RAM, I'd do a lot of tweaking and testing but in the long run I'd end up using a RAMdisk for several different things, one of them being page file duties as well.

The fact that SSD hardware doesn't have "spinning plates" doesn't save it from performance issues. SSD hardware can't read and write at the same time, just like a physical hard drive can't, and the random write issues (even with the best SSD hardware) kills performance overall. There are ways to use work arounds to alleviate the random writes, actually, but that's another thread altogether... :D

[TheFaz]

Thanks, Joe.

You mentioned something about TWO paging files, one on each disk? I've never heard of that before-- always thought it was one file and one file only.

Maybe I read your reply wrong?

[Joe Average]

You can put page files on most any storage media these days, of course hard drives are preferred even over SSDs since they offer the fastest write speeds for random operations - but SSD will overtake 'em fast.

When you bring up the Advanced System Properties under the Performance tab, then Advanced, Virtual Memory, you'll see something like this (I'm running XP Pro x64, obviously, but XP 32 bit and even Vista should still retain the basic look and functionality of this option):

http://img70.imageshack.us/img70/521/pagefileoptionsot1.png

When you highlight another drive in the list, you can add a page file to each, or just one, etc. as you see fit. Note I'm talking about physical hard drives and not just partitions on a single drive.

Putting page files on separate partitions on the same physical drive is a humongously bad monumentally horrible idea, so don't do it. Performance will simply plummet...

But page files on separate physical drives is highly recommended, and if possible, do it on a cleanly formatted partition at the beginning of each physical drive to ensure the fastest possible read/write performance for that given page file, also.

Putting multiple page files all over one physical drive with multiple partitions is bad because it would just force the drive to jump the heads all over the place, and of course you'd still be stuck with the read or write limit at any given moment - you can read data, or write data, but not both at the same time.

With two or more physical drives, that read/write limit disappears and Windows will multitask much better overall. If you do plan to put multiple page files across multiple physical drives, I'd say make each one 1GB in size, no more, no less (static page file, set the size for 1024 minimum and 1024 maximum in the properties box pictured above, or whatever). That's more than enough for any PC on the planet these days...