The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
Why You Should Want an SSD
For the past several months I’ve been calling SSDs the single most noticeable upgrade you can do to your computer. Whether desktop or laptop, stick a good SSD in there and you’ll notice the difference.
I’m always angered by the demos in any Steve Jobs keynote. Not because the demos themselves are somehow bad, but because Jobs always has a perfectly clean machine to run the demos on - and multiple machines at that. Anyone who has built a computer before knows the glory of a freshly installed system; everything just pops up on your screen. Applications, windows, everything - the system is just snappy.
Of course once you start installing more applications and have more things running in the background, your system stops being so snappy and you tend to just be thankful when it doesn’t crash.
A big part of the problem is that once you have more installed on your system, there are more applications sending read/write requests to your IO subsystem. While our CPUs and GPUs thrive on being fed massive amounts of data in parallel, our hard drives aren’t so appreciative of our multitasking demands. And this is where SSDs truly shine.
Before we go too far down the rabbit hole I want to share a few numbers with you.
This is Western Digital’s VelociRaptor. It’s a 300GB drive that spins its platters at 10,000RPM and is widely considered the world’s fastest consumer desktop hard drive.
The 300GB VelociRaptor costs about $0.77 per GB.
This is the Intel X25-M. The Conroe of the SSD world, the drive I reviewed last year. It costs about $4.29 per GB; that’s over 5x the VelociRaptor’s cost per GB.
The VelociRaptor is the dominant force in the consumer HDD industry and the X25-M is the svelte bullfighter of the SSD world.
Whenever anyone mentions a more affordable SSD you always get several detractors saying that you could easily buy 2 VelociRaptors for the same price. Allow me to show you one table that should change your opinion.
This is the Average Read Access test from Lavalys’ Everest Disk benchmark. The test simply writes a bunch of files at random places on the disk and measures how long it takes to access the files.
Measuring random access is very important because that’s what generally happens when you go to run an application while doing other things on your computer. It’s random access that feels the slowest on your machine.
| Random Read Latency in ms | |
| Intel X25-M | 0.11 ms |
| Western Digital VelociRaptor | 6.83 ms |
The world’s fastest consumer desktop hard drive, Western Digital’s 300GB VelociRaptor can access a random file somewhere on its platters in about 6.83ms; that’s pretty quick. Most hard drives will take closer to 8 or 9ms in this test. The Intel X25-M however? 0.11ms. The fastest SSDs can find the data you’re looking for in around 0.1ms. That’s an order of magnitude faster than the fastest hard drive on the market today.
The table is even more impressive when you realize that wherever the data is on your SSD, the read (and write) latency is the same. While HDDs are fastest when the data you want is in the vicinity of the read/write heads, all parts of a SSD are accessed the same way. If you want 4KB of data, regardless of where it is, you’ll get to it at the same speed from a SSD.
The table below looks at sequential read, sequential write and random write performance of these two kings of their respective castles. The speeds are in MB/s.
| Sequential Read (2MB Block) | Sequential Write (2MB Block) | Random Write (4KB Block) | |
| Intel X25-M | 230 MB/s | 71 MB/s | 23 MB/s |
| Western Digital VelociRaptor | 118 MB/s | 119 MB/s | 1.6 MB/s |
If you’re curious, these numbers are best case scenario for the VelociRaptor and worst case scenario for the X25-M (I’ll explain what that means later in the article). While the VelociRaptor is faster in the large block sequential writes look at the sequential read and random write performance. The X25-M destroys the VelociRaptor in sequential reads and is an order of magnitude greater in random write performance. If you’re curious, it’s the random write performance that you’re most likely to notice and that’s where a good SSD can really shine; you write 4KB files far more often than you do 2MB files while using your machine.
If the table above doesn’t convince you, let me share one more datapoint with you. Ever play World of Warcraft? What we’re looking at here is the amount of time it takes to get from the character selection screen into a realm with everything loaded. This is on a fully configured system with around 70GB of applications and data as well as real time anti-virus scanning going on in the background on every accessed file.
| WoW Enter Realm Time in Seconds | |
| Intel X25-M | 4.85 s |
| Western Digital VelociRaptor | 12.5 s |
The world’s fastest hard drive gets us into the game in 12.5 seconds. The Intel X25-M does it in under 5.
SSDs make Vista usable. It doesn’t matter how much background crunching the OS is doing, every application and game launches as if it were the only thing running on the machine. Everything launches quickly. Much faster than on a conventional hard drive. If you have the ability, try using your system with a SSD for a day then go back to your old hard drive; if that test doesn’t convince you, nothing will.
That’s just a small taste of why you’d want an SSD, now let’s get back to finding a good one.
Facebook
Twitter
RSS
250 Comments
View All Comments
ryedizzel - Thursday, March 19, 2009 - link
Anand,I just wanted to thank you for an amazing article. I am a very picky buyer and technology critic, so I always come to your site for the ‘real’ story on things. In fact for the amount of time, research, and (useful) testing methodologies you invest, I almost feel guilty receiving this information for free. Especially since your findings benefit the industry as a whole since it causes manufacturer’s to fix/improve their products (well at least the smart ones do). The i7 motherboard roundup was another great example of this. Seriously, if you have a place for donations I would send you $50 in a heartbeat. I know it’s not much but if others did the same it would add up to a decent token of appreciation.
Oh and please don’t take people’s grammar or nitpicky corrections the wrong way. Yes it can be annoying, but in the end it does help the article become closer to perfect since others catch little things overlooked by human error. In the end we are all grateful for these articles, otherwise we wouldn’t be here reading them!
bsoft16384 - Thursday, March 19, 2009 - link
You know, the JMicron SSDs really aren't so bad. Yes, you'd have to be crazy to spend $400 on one when there are better options like the X25-M (or the new Vertex series for that matter).But I paid $65 for my 30GiB OCZ "Core" SSD. Yeah, random writes are piss slow. I knew this. The drive replaced the 5400.5 that came with my EEE PC.
I'm not going to be doing any 'extensive multitasking' on my EEE. I'm not running a file server, I certainly don't have antivirus in the background, and I don't spend all day installing new apps.
I'm running 7. Compared with the 5400.5, the system boots faster, Chrome loads faster, but Windows updates take longer. That's a trade-off I'm willing to deal with, considering that I get less noise and more battery life in return.
I can tell you this - the JMicron SSDs beat the pants off of the PCIe MLC SSDs that ship with many netbooks.
So, yeah, I guess this is a product that's "unfit for market". But it's perfect for some of us. If I wanted a boot drive for a Linux media/backup server (along with HDDs for storage), I could see choosing a $50 SSD over a $50 HDD.
It's all about your needs. No one is pretending that JMicron SSDs are fast, at least not at writing. But if your usage is mostly read-centric (or "nothing-centric", as is frequently the case on netbooks), and your chief criteria are low power and low price, the JMicron SSDs do quite well.
petersterncan - Thursday, March 19, 2009 - link
Anand,That was an awesome article... and good for you to give OCZ to do the right thing... and they did!
Kudos also to OCZ for actually listening to feedback and doing something about it.
Adul - Thursday, March 19, 2009 - link
Good work Anand :)SSDMaster - Thursday, March 19, 2009 - link
The stuttering problem with SSD's can be fixed with diskpart. Go do some research before you post an article this massive and convoluted.goinginstyle - Thursday, March 19, 2009 - link
No it does not, it will help if the partition is properly aligned but it is not a cure, neither is the rest of the voodoo magic being spouted on the OCZ forums. They help, but do not cure the stuttering problem with the JMicron based drives. I just love the fact that OCZ wants to sell you a drive (Core series) that does not work properly, have you purchase third party software, and then hack the OS in order to improve the performance of the product. Glad to see it fixed with the Vertex and Summit drives though, but it will take a long time before I even think about using an OCZ product again. I was hoping to see the new ADATA and SuperTalent drives in this article, maybe those are coming in the next segment he mentioned.SSDMaster - Friday, March 20, 2009 - link
Yes, it does.I have a Core series 60GB OCZ drive. I bought it right before Newegg increased the price on the drives. The stuttering was horrible, and worthless even as a secondary drive if it was formatted with XP. Also, after using Diskpart and aligning the drive I could not install XP on the drive and have it bootable.. Which sucked.
But there's ways around that, and guess what, I have a stutter free flash drive for cheap that gets very good performance numbers, and boots Server 2008 in under 10 seconds.
bsoft16384 - Thursday, March 19, 2009 - link
OCZ's product works fine. You may not like the performance, but it's certainly not unusable.The $65 I paid for my 30GiB OCZ "Solid" SSD is about what you'd pay for a USB flash drive. The disk I have has a USB interface, which is very convenient, plus it's plenty fast enough for my EEE PC.
I'm glad that Anand has done these reviews. People need to understand what they're getting into when they by a JMicron SSD. If you don't expect much, you won't be disappointed.
Arguably for a normal notebook/desktop you should buy a normal hard drive if your budget is under $100. But the JMicron SSDs do a good job in netbooks (which, again, aren't too fast to begin with) at a very low price.
I have aligned my partitions and disabled swap on my Windows 7 install (on my EEE). I also have 2GB of memory in my EEE. I haven't done any fancy tweaking on the OS.
Compared with the EEE 900A that I had briefly (PCIe SSD), my EEE 900HA is dramatically faster. You can't run XP or Vista on PCIe SSDs unless you have a lot of patience. You *can* run it on a JMicron SSD.
I honestly don't notice any stuttering. I don't run antivirus and I don't multitask much on this machine. If I demanded from my EEE what I demand from my desktop (Q9300 + 8GB + WD6400AAKS), I know that the SSD would choke up. But I'm not going to do that on a 1.6GHz single-core Atom anyway.
So, yeah, OK. I guess I think that trashing JMicron SSDs is a little like trashing USB flash drives for being slow. Paying $300 for a UFD would be stupid, as is paying $300 for a JMicron SSD. But in the sub-$100 category, you don't expect much.
When better SSDs drop below $100, maybe I'll upgrade. Until then, I'm enjoying 5 hours of battery life on my 900HA.
tomoyo - Thursday, March 19, 2009 - link
Well I think it's unusable for my needs if I'm running it as an operating system drive. I place a giant important on the latency of the drive at that point and it certainly includes random writes. Which is why I would never ever buy an ssd that's majorly below the Intel write performance. It's not worth the price premium or loss of storage size compared to the standard hard drive.Bikerskummm - Thursday, March 19, 2009 - link
Fantastic article Anand!Just a few thoughts:
I have had some trouble replicating some of the Samsung SLC results...
Despite filling the drive up and emulating a well used drive as described in the article I cannot get my Sammy drive's performance to degrade as much as you managed to especially regarding random write performance...
Now my system used for testing is a socket 775 (qx9650) and I was testing on ICH9R and WINXP (SP3) but still I would expect to see similar figures ...
I do not have an X58 system to test on at the moment but I would be very interested if The Sammy SLC drives were shown to degrade faster / perform worse with a X58 / ICH10R / Vista x64 (SP1?) setup...