Best SSDs For The Money: August 2011
tomshardware.com
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A few months ago I had to help one of our scientists (the company is called 5AM Solutions.. they the awesome) run a bioinformatic job written in Perl and R. As it turned out, for long stretches of the processing the job required around 20 GB of memory. The one server that had all the required dependencies installed had only 8 GB at the time.
When I let the job run the first time, it started to page out memory to hard disk. The job ran for about four days, was only about 25% complete and during that time frame the server was un-useable for any other functions. Pretty much everything came to grinding halt.
Between that first run and the time our new RAM would be installed, just for grins, I gave the system 30 GB of swap space on the locally attached SSD. With that configuration the job finished in 19 hours and during that time the server was still responsive of other tasks.
When we finally added the appropriate amount of physical RAM the job took only 15 hours to complete.
It is the first time I have ever seen virtual memory be useful.
Virtual memory is what lets us write programs pretending that we own the entire address space, and it is very useful.
Swapping pages to disk, though, has been useful for a very long time. Yes, once your high-performance application starts swapping all the time, your performance is going to suffer by several orders of magnitude. But occasionally swapping pages in and out of disk is part of what makes modern operating systems useful. You left a large PowerPoint presentation open for several days, but never got around to working on it? Not a problem, since if the OS needs that memory, it will just swap out the pages. Without that ability, the OS would need to go around killing processes. (Which it will do if it has to, but it's a rare event because it can swap out pages.)
Paging out to a normal "disk" was not even an option, the performance ranged incredibly horrible to completely unusable.
Paging out to SSD was not only usable, it was only a percentage slower than 'real' RAM.
I think that's amazing. Having the option to use SSD as memory in a pinch is a great 'win'.
But your system may not have 4 GB. So the operating system has a data structure called a page table that has the virtual to physical mapping for each process. The processor accesses this table (it caches it in something called a TLB) so that it can convert the virtual address to the physical address.
An example using small numbers. Your program has a pointer to data. That pointer may have value 800. Let's assume that the amount of memory on your system is only between 0 - 400. So the processor has to convert the value 800 to a value between 0 - 400. It's the operating system's job to maintain that valid mapping.
Why does this matter, and why is it so tied up with paging to and from disk? Let's say the OS pages out the page containing that data. Then, later, it's paged back in, but in a different physical location in memory. Your program still has the pointer value 800, but your program still works correctly because the operating system keeps track of where in physical memory 800, for your process, maps to.
People in the Windows world often say "virtual memory" when they mean "swap space" because Windows would call the amount of swap space "virtual memory size." But virtual memory is the technique described above. Read the Wikipedia entry from above, or read an operating systems textbook for a full discussion of it.
When I hear "virtual memory," I think of the computer science meaning. However, I am a researcher in high performance computing systems.
Still, an SSD makes this all better. When I was using virtual memory on a Ubuntu server and put the swap partition on an SSD, everything worked great. On a rotating platter, not so much.
I've never found that I had a really good reason to encrypt a drive yet, I'm kind of surprised to see a suggestion that this is the way things are done.
Why should you be encrypting your disks?
There are additional reasons for full disk encryption too, like ensuring that important system files have not been tampered with. Whether or not you want to go that far depends entirely on your level of paranoia.
For a home desktop, the cost/benefit may be a bit different, because the computer is exposed to less places and people. As with many things in security, you would need to calculate what is an acceptable risk to you versus the cost of mitigating that risk.
Edit: Reference https://www.infosecisland.com/blogview/13722-SSDs-and-the-Im...
In addition to doing data recovery for people (sensitive documents, photos, etc.), I have a few clients I do work for and I'm exposed to client lists, password files, software license keys, etc.. If my home-office machine were ever stolen, I never need to worry since I use full-disk crypto.
Also, how does your encrypted-fs affect HDD performance?
The reason that I know that this is not just encryption overhead is because when asked about lower performance being seen by users who were not encrypting, OCZ staff confirmed on their forums that benchmarks not using compressible data will see lower numbers.
I googled a bit and saw that it's widely documented that sandforce are compressing right in the controller, and this allows it to physically do less reading/writing, which artificially inflates the data transfer speed.
Attempting to compress encrypted data has no effect on the size of the data whatsoever, so tests doing that are more reflective of their actual performance.
To their credit, OCZ did replace the drives promptly and without hassle. The 60GB replacement hasn't failed (albeit again under light use). The 240GB is on a Fedex truck for me today, so we will see on that one.
I put a 300GB Intel 320 in the ThinkPad about three months ago. No problems at all with it, but time will tell!
The Intel drive has better utility software - you can do a secure erase, for example. OCZ doesn't provide a utility like that. There are open source utilities and such, but it can be pretty chancy getting them to work (I never succeeded).
An aside: I kept the ThinkPad's hard drive and put it in an Ultrabay adapter replacing the optical drive. Large and less frequently accessed files (photo, video, downloads, etc.) go there. This gives lots of extra storage and should save wear on the SSD (not that it helped the OCZ any).
The hard drive is set to turn off after a few minutes even on AC power, so it sits idle most of the time. When I do need an optical drive I use a USB one, or I can swap the original drive back in.
The first OCZ was a Vertex 2 180GB and failed after 1 month. I got it RMA'd and received my second Vertex 2. That one failed after 2.5 months.
Both intels are still running strong. I'm also surprised to see the OCZ's so strongly recommended. The RMA process sucked both times and the second time is working out to be a refund. I haven't received the refund yet, but at least there is a process.
The first was when my current system was new two years ago. I was never able to get it working.
The second lasted a year and a half before it started corrupting files before finally dying.
The third lasted almost two whole weeks before I received a BSOD while gaming and a no longer detected SSD.
All three of these requires some form of CMOS reset/firmware fiddling to get running initially.
At least the Vertex 2 seems fine so far. But overall, I'm not too impressed with OCZ. I'll give them credit for replacing the drives without much fuss, but the last two RMAs took around 2 weeks to receive the replacement. Which is a huge pain in the ass when it's your OS drive in your rig.
OWC's customer service was stellar though. Every time I called the phone was answered by a tech (an engineer I suspect) who very much knew what he was talking about and never wasted my time with scripts. After one failed fix -- it looked like zapping PRAM had fixed it, but it didn't -- they mailed me a new drive and I returned the old in its packaging. The new drive has been running fine since February.
bitter crap
As an example of the effects it has had on my computer performance, building my upcoming book (which invokes rake and JRuby) used to take 1m 30s on a 7200 RPM drive. Now it takes 15 seconds. Also, productivity apps like Office open in a split second.
Also, have you looked into 3g inside your macbook? Is there any way to make that work? A dual function wifi/3g mini PCIe?
About a month.
> and are you running Lion?
Yes.
> How did the upgrade go? Did you need anything besides Time Machine?
I did a clean install and then moved over my data. It was time for me to do a clean up anyway, so I took the opportunity to do so.
> Do you use macports, postgresql, or apache, and if so, any problems after the upgrade?
I use all the typical dev tools with no problems, but I have not installed macports after the switch to this new drive. (I use brew instead.)
> Also, have you looked into 3g inside your macbook?
I haven't.
> How long have you been running this drive
Since December 2010.
> And are you running Lion
I am now; prior to that, it was Snow Leopard
> How did the upgrade go?
The hardest part was trimming my 250 GB drive down to 160 GB; mostly this just involved wiping out old VMs, disk images, extra programs, etc. and only keeping a subset of my iTunes library (minus TV shows, etc) on the laptop.
> Did you need anything besides Time Machine?
I don't suppose I did, but for the sake of speed I just did an image of the drive (block copy, using Disk Utility).
> Do you use …, and if so any problems?
None at all. Things are generally much more responsive, especially in cases that involve scanning directories. Deleting large directories full of source code is dramatically faster. chown'ing the Linux kernel tree, for example, feels almost instantaneous in comparison.
One issue I did have that's worth mentioning: because I did a direct copy of my Snow Leopard install (which, in turn, had been upgraded from Leopard), I found that the performance of the system was not at all what I'd hoped. It wasn't unresponsive (beachballs disappeared entirely), but it certainly wasn't blazing fast.
When I took my current job, I imaged my SSD to a backup drive and imaged my new work laptop's fresh install to my SSD, and the difference was like night and day. Suddenly, my computer was a speed demon. If it weren't for having to type my password, I feel like it would have gone from power off to loaded desktop in ten to fifteen seconds or so. It was unbelievably fast.
So my suggestion is, image your old drive, do a fresh Lion install on the new drive, and then use the Migration Assistant or Time Machine restore to bring your user directory back (and get rid of all the junk your account loads when it starts up that it doesn't need to have).
In addition, most RMDBS are optimized for mechanical disks. Optimization for SSDs becomes interesting only recently when the price of SSD drops to be barely reasonable.
However, SSDs absolutely rocks as big cache.
Since SSDs blow the hell out of platters no matter what the workload or access pattern is, you'll still get significantly improved performances, even without SSD-specific optimizations.
The one "optimization" I'd like to see out of SSD's rise is deoptimization: since access patterns becomes less important (or at least naive access patterns become less costly), I'd like to see systems simplified and "optimizations" removed rather than new optimizations added.
The first thing we used to do is try to convince the hardware raid controller not to do anything clever, like readahead etc, b/c seek times are practically meaningless. Despite our efforts at disabling every optimization we could control that was tailored for rotational platters, we still found that software raid (linux md) outperformed a classically great hardware controller--perhaps by virtue of being "stupider".
So that is our go-to configuration now: Micron P300 SLC, 200GB drives, with md raid.
This might be a horrible example but my one friend had a installation of FileMaker Pro running on a completely tricked out XServer (RAID with 15K SAS drives). With 250 concurrent users he was completely max out on CPU and many queries took minutes to complete.
When he moved to a 256GB SSD his CPU load now never goes above 20% and not one query takes more than five seconds, period.
Also, please reference my old HN post from over a year ago.
Here is a benchmark I've run (vertical numbers are transactions/s, horizontal number of threads) : http://blogs.intellique.com/images/comp-ssd-db.png
http://eshop.macsales.com/shop/SSD/OWC/Mercury_Extreme_Pro_6...
Subjectively, I would describe my OWC 120GB drive as "blisteringly fast". Previously I had a 100GB OWC with extra redundancy for server loads (overkill in my iMac 2010) and the first time it booted it was like being personally greeted by the Flying Spaghetti Monster.
http://www.anandtech.com/show/4604/the-sandforce-roundup-cor...
I for one initially had picked up a 60 GB OCZ Vertex1 awhile ago and then about 10 months ago moved up to a 120 GB Vertex2. Will never look back.
What other criteria are there? GB/$, performance/watt, watts at idle, IOps, and warranty or lifecycle costs. Personally, I find something "big enough", ignore power consumption and iops (neither is going to make a huge enough difference for me to concern myself), and then get whatever I can find that has the longest warranty.
Considering the dinosaur pace of new interfaces, and the fact that SATA III isn't even fully "rolled out" yet, I wonder if we are going to see a new wave of hackish custom solutions by manufacturers. Dual SATA ports on your drive, anyone?
http://www.smartm.com/products/productdetailssd.asp?SMARTPar...
We may also see some migration from SATA to NVM Express.
Frankly it hasn't been the jaw-dropping entering-hyperdrive performance boost I had kind of hoped for (I'm a rails dev). While a definite improvement, it seems that for many of my most common tasks (read: tests) I have merely pushed the bottleneck back onto the CPU. But while it hasn't sped up all that much, it never slows down, which you don't notice at first but over time has a subtle confidence-building effect. Application launch speeds are much improved, for those who spend a good part of their day launching apps, which is not me. I tend to launch a few and then use them for the next two weeks before I restart. I also like how the drive does not make whining sounds when I move the computer before it's gone to sleep.
Recommended, anyway, they're cheap enough now that it's not a luxury, even if like me you use most of it for your work music collection.
I ended up getting a 128GB for the OS and apps and installed a macbook optical replacement HD caddy for a 500GB drive for media. If you can deal without an optical drive this config is highly recommended.
I think the difference is because if you only do one thing at a time and you have sufficient RAM, than an SSD does almost nothing. Whereas if you have a lot of processes running and accessing files spread around the drive, and HDD will quickly send you to beach ball land.
Parallels in particular will do you in in a hurry.
I'm in the habit of running a IE7/8/9 in separate Parallels instances, Photoshop, Safari/Firefox/Chrome/Opera, MacVim, MySQL w/ 20GB of data in it, local rails server, local rails console, and iTunes or Spotify.
With an SSD I basically just run whatever I want and things slow down only very slowly and linearly as I add processes. Without an SSD I feel like if I listen to music it's going to slow things down, it adds unnecessary mental overhead to my whole workflow. The mental factor is I think why people may overstate the absolute benefit of an SSD.
This is my experience as well. I have an older computer (2009) with a low-voltage processor (SU3700) that I am looking at upgrading, but it's not really justifiable yet.
So I thought I'd grab an SSD for a nice performance pick-me-up now, then throw it in my new computer when I got it.
However, while there is a performance increase, it isn't really all that noticeable. (I use another computer often with an HDD, and can hardly tell the difference.) The CPU is definitely the bottleneck on most tasks.
On the other hand, right after I upgraded my SSD, I went to ruby 1.9.2 and rails 3, which are much slower due in part to a bug that makes requiring files take forever.
I think this is because, although sandforce drives have native garbage collection, it can sometimes happen at a very inopportune moment (like say, a 20s "pause" during critical moments of a SC2 game).
What this does is actually pretty simple, it replaces the string “Apple SSD” (used to identify for which drives trim is turned on) in a file in the relevant kernel extension with zeros. It also creates a backup copy of the original file.
The Trim Enabler you linked to replaces a whole kernel extension (meaning you might end up with an older version of a kernel extension) which is obviously monumentally stupid.
find . -iname "*java" | xargs grep ...