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Wha's the truth about the SSD's dilemma ?

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August 30, 2012 8:05:00 PM

Hi forum,

Precisely and concisely, I would like to know your opinion about which s better:

1) Intel 520 Series Cherryville SSDSC2CW240A3K5 2.5" 240GB SATA III MLC Internal SSD.

OR

2) 2 SSDs Intel 520 Series Solid-State Drive 180 GB SATA 6 Gb/s 2.5-Inch - SSDSC2CW180A3K5 in in RAID 0 ?


Some people claim that with RAID 0 the speed of reading and writing is almost double and a better performance, While I read some others against RAID 0.


I would really appreciate your thoughts !

More about : wha truth ssd dilemma

a b G Storage
August 30, 2012 9:20:13 PM

Those against Raid 0 are against it because it disables the TRIM function, so it will accumulate garbage in the flash cells and degrade performance over time
a b G Storage
August 30, 2012 9:24:35 PM

djscribbles said:
Those against Raid 0 are against it because it disables the TRIM function, so it will accumulate garbage in the flash cells and degrade performance over time


Actually you can use the trim feature on Z77 boards in raid now on the Intel controllers.
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August 30, 2012 9:38:40 PM

Thank for your inputs.

But what about my original question ?

Which one has a better performance:

1) Intel 520 Series Cherryville SSDSC2CW240A3K5 2.5" 240GB SATA III MLC Internal SSD.

OR

2) 2 SSDs Intel 520 Series Solid-State Drive 180 GB SATA 6 Gb/s 2.5-Inch - SSDSC2CW180A3K5 in in RAID 0 ?


I mean, If I am building a new PC, which option should I go with ?
a b G Storage
August 30, 2012 9:40:05 PM

speed wise, there is no difference in performance between the 180GB/240GB Intel Cherryville drives. I did just upgrade from a 120GB to a 180GB and was surprised that the difference was slightly noticable (specifically at boot).

If your motherboard support TRIM within the SATA ports specifically setup for RAID, then feel free to double your read/write speeds.

For me, that would be totally overkill - I just game and encode video. Just a single 180GB is insanely fast to the point where everything feels instantaneous. Don't know what you're running or what your expectations are, but I would be surprised if you needed the additional IO - it's just amazing with just a single drive.
a c 87 G Storage
August 30, 2012 9:46:07 PM

sameronline said:
Hi forum,

Precisely and concisely, I would like to know your opinion about which s better:

1) Intel 520 Series Cherryville SSDSC2CW240A3K5 2.5" 240GB SATA III MLC Internal SSD.

OR

2) 2 SSDs Intel 520 Series Solid-State Drive 180 GB SATA 6 Gb/s 2.5-Inch - SSDSC2CW180A3K5 in in RAID 0 ?


Some people claim that with RAID 0 the speed of reading and writing is almost double and a better performance, While I read some others against RAID 0.


I would really appreciate your thoughts !


Up until very recently (a few weeks ago) it was impossible for the TRIM function to work on SSDs that were put in RAID-0.

File deletion works at the file system level and each file system has its own mechanism for deleting files. When a file is deleted, the file is only "flagged" as deleted in the directory and allocation units (clusters or blocks) are marked as free for use. This means that the allocation units that contained the information of the deleted file are left completely untouched. This is what allows data to be undeleted. There exists no mechanism to actually "delete" data from a hard disk, the traditional way to ensure that data is wiped from a hard disk is to write over it with random data, a pattern, or zeroes.

Platter drives are logically addressed such that a particular allocation unit can always be mapped to a particular set of physical sectors, by default most clusters or blocks contain 8 sectors totalling 4 kilobytes. Writing new data to an allocation unit on a hard drive simply writes over the old data and there is no difference in performance when a sector is written for the first time or the 1000th time.

SSDs on the other hand do not have a straight mechanism for mapping logical blocks to physical blocks, the SSD controller shifts them around internally to reduce wear and tear. Blocks in an SSD can also be erased or "zeroed out", in fact they must be. When an SSD overwrites a physical block it must first erase it and then write the new data; this is a two stage operation.

When an SSD overwrites a logical block it will first try and write to a free physical block and point the logical block to the newly written physical block. The old physical block is then marked as garbage and will be erased later on when the drive runs its internal garbage collection routine.

So what does TRIM do?

Trim allows the operating system to tell an SSD that a particular logical block no longer contains useful data and can thus be erased. On platter drives this was never necessary because it didn't matter, writes and rewrites were the same. Without TRIM the SSD will eventually become nearly 100% full of written physical blocks even if the file system is full of logically free blocks. This is because a block that is freed up in the file system still contains the data that was on it when it was freed up. This turns almost every logical "write" operation into a physical "rewrite" operation which reduces performance on SSDs. With TRIM support the OS tells the SSD that the logically freed blocks can actually be physically freed as well. This allows the SSD to erase the contents of the block when it is convenient to do so and not when it is necessary to rewrite it.
August 31, 2012 6:20:26 AM

@Pinhedd

Thank you so much for your thoughtful response. I really appreciate that you took the time to explain all this.

I am trying to build a new super powerful PC:

- Motherboard: ASUS P9X79PRO
- CPU: Intel Core i7-3930K
- RAM: G.SKILL Ripjaws X Series 32GB (4 x 8GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800).

Also, I don't play games at all and I don't edit video clips or do any graphics processing at all. So, I really don't want to spend much money on the graphic card (Probably maximum 80 USD).

I am working with Virtual machines, SharePoint 2010 and SharePoint 2013 which eat SO MUCH RAM and need REALLY super powerful CPU.


So, If you are in my shoes, Would you buy (1) or (2) :

1) Intel 520 Series Cherryville SSDSC2CW240A3K5 2.5" 240GB SATA III MLC Internal SSD.

OR

2) 2 SSDs Intel 520 Series Solid-State Drive 180 GB SATA 6 Gb/s 2.5-Inch - SSDSC2CW180A3K5 in in RAID 0 ?


???
a c 87 G Storage
August 31, 2012 3:07:57 PM

Get the single 240. The performance difference between a single SSD and two SSDs in RAID-0 is mostly synthetic so unless you're trying to break a benchmark record there's no real benefit to putting SSDs in RAID-0. Having a single 240 allows you to put another 240 in later on if you like. Please keep in mind that the X79 chipsets use the Rapid Storage Technology Enterprise ROM rather than the standard Rapid Storage Technology ROM. The drivers are different too.

EDIT: Unrelated advice but as soon as you get the P9X79 board you should update the firmware as soon as possible
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