The SSD Diaries: Crucial's RealSSD C300
by Anand Lal Shimpi on July 13, 2010 12:39 AM ESTLife just isn’t fair. When I met with Crucial at CES to talk about its first foray into the high performance SSD market I was given very high expectations for reliability and the testing that Crucial would put the drive through. We talked about the failure of other controller vendors to do adequate testing. Even Intel’s own follies. Crucial assured me that validation testing was high on the priority list.
The company already tests hundreds if not thousands of configurations for its memory. Slotting SSDs into the mix wouldn’t be difficult. In contrast, most of the vendors who ship Indilinx and SandForce drives don’t have nearly the validation experience or infrastructure in place to gain it.
Then, just weeks after I got my C300, the drive stopped working. Crucial sent me another drive which didn’t die, but let me discover that the C300 had serious issues when it came to worst case scenario performance. Similar to the original X25-M firmware when given a random enough workload, the RealSSD C300 could be backed into a corner that it would never get out of.
I dropped the C300 from my list of even potential recommendations while Crucial worked on a fix. Meanwhile SandForce’s partners had been shipping drives, with relatively few problems. To make matters worse? The majority of SandForce drives that shipped while Crucial suffered used release candidate firmware. Mass production firmware wasn’t distributed until later. And SandForce did nothing to stop it.
The moral of this story is that entering the storage market is still new territory for everyone. Company size, whether small or large, doesn’t dictate whether you’ll face a failure from a new product. The only guarantee you have is the experience of others who’ve used the drives in configurations similar to your own.
Which brings me to todays topic. I’ve been testing Crucial’s fixed firmware and so far things look good. The situation has improved enough to warrant another look at the C300, including its more affordable 128GB version. And that’s exactly what we’ll do today.
The Drive
I’ve explained how SSDs work in great detail here and here, if you’re a newcomer to all of this I’d suggest looking over those articles.
Like most SSD vendors, Crucial turned to a third party to supply a controller for its SSD - Marvell. Inside Marvell’s controller is a pair of ARM9 CPUs that work in parallel. One core handles SATA requests while the other handles NAND requests.
On the SATA side is a 6Gbps interface, a significant upgrade from the 3Gbps controllers found on all other SSDs we’ve reviewed. If you’ve followed our SSD coverage you’ll know that sequential read speed is one area where SSDs are traditionally limited by 3Gbps SATA. The C300 should fix that. To feed the controller Crucial uses ONFI 2.0 NAND with higher max transfer rates.
While the controller is made by Marvell, the firmware is entirely Crucial’s design. As we’ve seen in the past, as long as the controller’s CPU is fast enough the biggest influence on SSD performance is the architecture of the firmware.
Paired with the controller is an absolutely massive 256MB DRAM. The Marvell controller has a smaller cache than what Intel outfits its X25-M G2 with and rather than demand a more expensive controller with a larger cache, Crucial uses a very large external DRAM to store mapping tables and access history. Micron, Crucial’s parent company, being a DRAM manufacturer probably played a role in making that decision.
The RealSSD C300 is available in three capacity points, two of which I’ll be looking at today: 64GB, 128GB and 256GB. The Crucial controller has 8 channels to its NAND. Both the 128GB and 256GB versions have all 8 channels populated, however the 256GB drive physically has more die per NAND package which allows for greater parallelism and potentially higher performance.
Like the Intel and Indilinx drives, Crucial dedicates around 7% of the drive’s capacity to spare area. This non user-addressable NAND is used as a pool of clean blocks to replace dirty ones during normal use, and to replace any bad blocks.
| Pricing Comparison | |||||||
| Drive | NAND Capacity | User Capacity | Drive Cost | Cost per GB of NAND | Cost per Usable GB | ||
| Corsair Nova V128 | 128GB | 119.2GB | $319 | $2.492 | $2.676 | ||
| Crucial RealSSD C300 128GB | 128GB | 119.2GB | $369 | $2.883 | $3.096 | ||
| Crucial RealSSD C300 256GB | 256GB | 238.4GB | $660 | $2.578 | $2.768 | ||
| Intel X25-M G2 160GB | 160GB | 149.0GB | $405 | $2.531 | $2.718 | ||
| Intel X25-M G2 80GB | 80GB | 74.5GB | $215 | $2.688 | $2.886 | ||
| OCZ Vertex 2 120GB | 128GB | 111.8GB | $329 | $2.570 | $2.943 | ||
| OCZ Vertex 2 240GB | 256GB | 223.6GB | $640 | $2.500 | $2.862 | ||
High end SSDs have dropped in price considerably over the past couple of months. While 100GB SandForce drives were once at or above $400, these days you can get 120GB extended capacity versions for $330. In fact, the price of SandForce drives have dropped so much that there’s pretty much no reason to buy an Indilinx drive at this point. Note that there's no tangible performance difference between the extended capacity SandForce drives and the older versions with more spare area for any of the workloads we'll be talking about today.
Crucial’s C300 is priced competitively with the market, but it does command a price premium over the equivalent capacity SandForce drive. While OCZ will sell you 128GB of NAND on its Vertex 2 for $2.57/GB, Crucial asks for $2.883/GB on its C300.
The Test
| CPU | Intel Core i7 965 running at 3.2GHz (Turbo & EIST Disabled) |
| Motherboard: | Intel DX58SO (Intel X58) |
| Chipset: | Intel X58 + Marvell SATA 6Gbps PCIe |
| Chipset Drivers: | Intel 9.1.1.1015 + Intel IMSM 8.9 |
| Memory: | Qimonda DDR3-1333 4 x 1GB (7-7-7-20) |
| Video Card: | eVGA GeForce GTX 285 |
| Video Drivers: | NVIDIA ForceWare 190.38 64-bit |
| Desktop Resolution: | 1920 x 1200 |
| OS: | Windows 7 x64 |
Facebook
Twitter
RSS
51 Comments
View All Comments
Breit - Tuesday, July 13, 2010 - link
There are 4 different Vertex 2 drives from OCZ as i know:-> the standard Vertex 2, which uses MLC flash and has ~13% overprovisioning (~91GB usable capacity for the 100/128GB model)
-> then there is a Vertex 2e, which is the same as the normal Vertex 2, but with a modified firmware for ~7% overprovisioning (~111GB usable capacity for the 100/128GB model)
-> then there is a Vertex 2 pro, wich also uses MLC flash and also has ~13% overprovisioning, but also has a supercap to help out on a sudden power loss (more like an enterprise feature)
-> and an last there is the Vertex 2 EX: this drive uses SLC flash and therefor is way to expensive for normal desktop use
the first 3 should perform nearly identical. the last is supposed to be quite superior in performance, but i havn't seen any reliable performance numbers as of yet - anand? ;).
hotlips69 - Tuesday, July 13, 2010 - link
Thx for the info!Why would anyone buy the Vertex 2 "standard" over the Vertex "2e" if it performs the same, but has a larger usuable capacity?
Would there not be a performance hit if there is only 7% provisioning compared to 13% if the drive got full???
DanNeely - Tuesday, July 13, 2010 - link
In normal desktop use there's no reason to get the standard drive. Sandforce initially designed its controllers for the enterprise market and servers can be much more brutal on a drive than end user computers are. On a server workload the extra scratch space was useful, but when they moved over to consumer drives it had no benefit. The 2e was released with an updated firmware once it became clear the controller was just wasting space.jedighost - Tuesday, July 13, 2010 - link
Let me answer: there will be OCZ 'Vertex 2' firmware updates coming out that will allow you to "switch" between 100GB and 120GB on the same drive. So far no significant performance difference have been found, but time is an interesting factor here, noone had months or years to test it, and users who visit forums and write their experiences are usually not known for torturing their SSDs 24/7 just to see what happens/kill them/wear them out.Based on the data available at the OCZ Support Forums, grab the 100GB or 120GB version, whichever you can cheaper, and later on you will be able to choose how much provisioning you want, 7 or 13%.
When your 120GB Vertex 2 SSD is full and you write 8GBs of data (7% of 128GB) in a short period, yes, then there can be degradation. But how likely is that, really?
Also, in average, you can write an MLC cell 10,000 times before you wear it out. This means, to evenly wear out all the cells of your Vertex 2, you need to write 10,000x120GB=1200 TERABYTES on your drive. Sure, when you only write a smaller than 4KB file, the whole cell has to be rewritten, but still, as a system drive, which is not supposed to contain huge files, in the size of several Gigs (raided Raptors are for that), when will you write 1000 Terabytes? By that time, your SSD is long outdated, because 10 years passed by.
More concretely: if you write 275 GBs EVERYday to your SSD for 10 years, 365 days a year, then you wrote 1000 TBs. Lets say i didn't calculate with a bunch of factors, and I am wrong to 3:1 degree and your drives wears out in 200TBs, that is 100GBs a day for 10 years. When will you "rewrite" the whole size of your SSD in daily usage?
Catch my drift?
Buy your drive and don't worry, just enjoy it, the same as I did. Have regular backups as this is still new technology, but be ready to be blown away if this is going to be your first SSD - you will realize that it was not stronger CPUs and overclocking that was needed to make a system snappy, but eliminating the most-overlooked bottleneck: the old HDD.
jedighost - Tuesday, July 13, 2010 - link
Actually i made a quick calculation: assuming you can write with 100MB/sec to your Vertex 2 continuously, 24/7, it would still take *120 days* to wear out all the cells, writing to them 10,000 times each. No mortal user had the time to try this yet. :))sor - Saturday, December 11, 2010 - link
FYI, in December '09 Micron announced that their MLC write durability increased significantly. Anything that has their 34nm chips (C300, maybe others) will have much better durability than your figures.Drazick - Tuesday, July 13, 2010 - link
It seems the smart move would be waiting for the next generation of SSD's by Intel.Assuming it would be a SATA 3 drives paired with P65 it should beat anything on the table at the moment.
Jonathan Dum - Tuesday, July 13, 2010 - link
Not to mention 25nm NAND from Intel/Micron... longest wait ever. Though I wonder when all the other guys like OCZ will get 25nm?james.jwb - Tuesday, July 13, 2010 - link
Anand, what are your recommendations for around the 60-80GB mark? Any changes from your conclusion above?Phate-13 - Tuesday, July 13, 2010 - link
I will say it again, and keep saying it till it happens. Most people are not interested in 100-300GB SSD (except for lower prices obviously) or in 30-40GB SSD's. It's the 50-80GB ones that most people are interested in. That's about the sweet spot of capacity that is needed.The Crucial RealSSD C300 64GB is x times more interesting then it's bigger brothers, it's much cheaper, not only in absolute terms, but also in capacity/euro. And by far the best buy atm in my eyes.
The line-up I want to see would be about something like this:
- Kingston V-series S2 64GB
- Western Digital SiliconEdge Blue 64GB
- Crucial RealSSD C300 64GB
- OCZ Solid II 60GB
- OCZ Onyx 64GB
- OCZ Agility 2 60GB
- OCZ Vertex 2 60GB
- Corsair Force 60GB
And perhaps some of the other, cheaper Corsair SSD's.