Page files on SSDs (or swap partitions)

[Jeremy Collake]

When SSDs first came out their lifespan was much lower than now, and they were a lot more expensive. People wanted them to live as long as possible, so they came up with the recommendation to never place a page file on an SSD. This was sad, because an SSD is perfect for a page file since I/O is typically in small 4KB random requests.

Things have changed. The lifespan's of FLASH chips inside SSDs has improved, the wear leveling technologies in the SSD controllers has improved, and the cost of SSDs has come down. It is now safe to put your page file on an SSD. By the time it wears out, a typical HDD probably would have too, and regardless you'd likely be wanting to update that now ancient SSD. In a worst case scenario you would prematurely 'degrade' performance I suppose, as that is how SSDs start to show wear.

In my opinion, the days of worrying about your SSD lifespan are over. Sure, you could go try to intentionally kill one if you wanted, or degrade its performance, but in normal utilization, you are going to be fine, in my opinion.

UPDATE: Also see below for my recommendation to use an SSD as a ReadyBoost cache store (yes, you can do that). ReadyBoost is ideally suited for SSDs - a 'smart cache' made for that type of media. If you have any uncomfortable feeling about putting a page file on an SSD, try ReadyBoost instead.

[peterhayes]

I didn't think that the problem was to do with premature wear but that SSD's (the early ones anyway) were slower in the 4K random writes area ie slower than a conventional HDD and the paging file would be better on a fast conventional HDD like a VRAP or now the latest Seagate (Barracuda Xt, Black Armor), SATA 6GB drives. Has that changed?
Thanks
PeterH

[Jeremy Collake]

I didn't think that the problem was to do with premature wear but that SSD's (the early ones anyway) were slower in the 4K random writes area ie slower than a conventional HDD and the paging file would be better on a fast conventional HDD like a VRAP or now the latest Seagate (Barracuda Xt, Black Armor), SATA 6GB drives. Has that changed?

First, it should be noted that even if early SSDs were slower in 4KB random writes due to the read-erase-write cycle that must be completed for the whole block, they were much faster in 4KB random reads. Which is more essential? Reads, by far. Why? Writes can be deferred and cached, while reads must be made immediately to accommodate the current hard page fault (request for memory to be loaded into RAM). You can improve the situation further by not forcing write cache flushing (an option in the drive hardware policies).

I am pretty certain any recent SSD would outperform HDDs in 4KB random reads *and* writes, but I haven't verified that. I'll leave that as an exercise to the reader. However, even if they were slower in 4KB random writes, 4KB random reads are much, much more important. A quick empirical test on a system here shows that moving the page file to an older SSD made a HUGE difference in performance. I mean, this isn't something that was marginal or debatable, it was a very perceptible improvement.

Of course, for HDDs you have seek time to contend with that is exacerbated by additional concurrent I/O to the HDD. This is not reflected in most synthetic benchmarks. There is of course no seek time for SSDs.

If you are uncomfortable with putting a page file on an SSD, you could consider using your SSD with Vista+'s ReadyBoost. It is designed as a 'smart cache' for flash memory (including knowing that random writes can be a bit slow), so is ideally suited for SSDs. It writes out the most actively referenced 'stuff' to the SSD at bootup, keeps it updated periodically, then has a quick place to pull it this data from when needed. Perfect for SSDs.

Many users do not realize they can use their SSDs as ReadyBoost caches, but indeed you can

[gamesturbator]

I didn't think that the problem was to do with premature wear but that SSD's (the early ones anyway) were slower in the 4K random writes area ie slower than a conventional H
If you are uncomfortable with putting a page file on an SSD, you could consider using your SSD with Vista+'s ReadyBoost. It is designed as a 'smart cache' for flash memory (including knowing that random writes can be a bit slow), so is ideally suited for SSDs. It writes out the most actively referenced 'stuff' to the SSD at bootup, keeps it updated periodically, then has a quick place to pull it this data from when needed. Perfect for SSDs.

Many users do not realize they can use their SSDs as ReadyBoost caches, but indeed you can

I am wondering, being wholly ignorant, if RB can be used on your OS SSD or if it has to be a dedicated SSD or would you simply make a dedicated partition on the SSD. Additionally, any benefit to having BOTH the paging file and RB on the same SDD? Thanks.

[Jeremy Collake]

I do not know if Windows allows such or not, but I would guess it doesn't. There are too many variables to predict how it might affect the overall system performance if you were to do that. If you've got complimentary hard drives that are often referenced, then it is possible some benefit might be derived from doing that, though that's the only scenario where I can imagine it being beneficial. If the ReadyBoost cached data is all stuff *on* your SSD, then it obviously isn't going to make it faster.

[gamesturbator]

Thanks. I've never used RB as I usually had enough memory. I just didn't understand it that much to begin with. Stupid Gigabyte board has memory slots WAAAAY too close together, so can't install all 4 sticks or they'll overheat immediately, so I have 4 instead of 8GB.  After reading your thread I decided to let Windows manage my paging file on the SSD and took off my paging file from my spinner drive, as I was told having a second paging file wouldn't be that beneficial, especially if it's on an ordinary HDD.

[nikkil]

+1 right here.

[zong333]

Yes, this is the default setting.
After you update the AHCI driver, like IRST(Intel® Rapid Storage Technology), it will reset to default setting.

[BenYeeHua]

Yes, this is the default setting.
After you update the AHCI driver, like IRST(Intel® Rapid Storage Technology), it will reset to default setting.

Yes, Pakistan bot.
Do you want to build a snowman?

[Jeremy Collake]

LOL, thanks BenYeeHua.

If you can do me one more favor, don't post after these bots. I am watching you kill them, so don't worry I won't notice your efforts.

Thanks for keeping the forum clean!