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Samsung SSD 840 EVO MSATA Tested
MojoKid (1002251) writes "Shortly after 2.5-inch versions of Samsung's SSD 840 EVO drives hit the market, the company prepared an array of mSATA drives featuring the same controller and NAND flash. The Samsung SSD 840 EVO mSATA series of drives are essentially identical to their 2.5" counterparts, save for the mSATA drives' much smaller form factor. Like their 2.5" counterparts, Samsung's mSATA 840 EVO series of drives feature an updated, triple-core Samsung MEX controller, which operates at 400MHz. The 840 EVO's MEX controller has also been updated to support the SATA 3.1 spec, which incorporates a few new features, like support for queued TRIM commands. Along with the MEX controller, all of the Samsung 840 EVO mSATA series drives feature LPDDR2-1066 DRAM cache memory. The 120GB drive sports 256MB of cache, the 250GB and 500GB drive have 512MB of cache, and the 750GB and 1TB drives have 1GB of cache. Performance-wise, SSD 840 EVO series of mSATA solid state drives performs extremely well, whether using synthetic benchmarks, trace-based tests like PCMark, or highly-compressible or incompressible data."
Shouldn't this submission feature an orange "Ad" image similar to Google's paid results instead of the "Hardware" image?
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But it fits in an mSATA port which means more compact notebooks (don't need room for a 2.5") or faster notebooks with big-storage (mSATA SSD + 2.5") or used as an bios-level accellerator with certain bioses that can only use mSATA port for this.
Yes. The SSD systems are not reliable enough to act as registers yet, and would impose a noticeable pre-processing penalty for those highly optimized, low-level operations that use memory registers.
Yes. One of the best ways to avoid wearing cells is to cache writes aggressively, in the hope that either 1) another write will simply write over the top of that one, or 2) another write will fill in the rest of the cell, so that you don't have to erase a cell for a partial write.
RAM is still much faster than flash.
Sure, but the OS operating the drive has its own RAM cache.
There are only a few reasons to put a cache on a drive that I can think of:
1. If the RAM is battery-backed then writes to the drive cache can be treated as writes to the drive itself.
2. If the physical operation of the drive is abstracted from the OS, then it may only be possible to optimize out-of-order writes by utilizing a cache at the hardware level. For example, an OS might write a consecutive series of blocks, but perhaps one of those blocks was remapped by the drive to a different cylinder making it MUCH cheaper to write that one block later.
3. A variation of #2 is that on SSD the erase and write operations operate on different sized blocks, so there might be other optimizations the controller can make if it can perform operations out-of-order.
So, RAM being faster on its own isn't really a driver for putting a cache on a drive (just spend the money on more system RAM, where it can be used more flexibly). However, a RAM cache allows the drive to do other optimizations on writes not possible at the OS level.
Mine has one*, and that certainly doesn't seem to slow it down.
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*Yes, I actually just set up a new machine that has a 2.5" Samsung 840 EVO-0 SSD, and it rocks. OFF to kdm login screen in about 2 seconds.
I believe that I've not enjoyed a new piece of tech so thoroughly since microwave ovens first came out.
Il n'y a pas de Planet B.
For mere consumers it's a great drive. If you need that level of data assurance you're looking at the wrong SSDs, go look at Intel SSDs but be prepared to pay an arm and a leg for it. For us mere mortals it's still a great drive.
Actually I cannot think of any scenario, where I would use such a drive. We have lost 3 desktop drives which has no capacitors. One is still working. Meanwhile there are no issues with four drives which has capacitors.
SSD do much better when mated to a highly optimized controller that does a lot of background work tailored specifically to flash memory. OS has no idea about any of that - it just has some basic cache management and TRIM. It probably wouldn't either - this stuff is typically trade secret and the reason why SSD controllers are so important for performance of the drive.
No file system can deal with the situation when data synced to drive is lost. And that is the better case for SSD in case of a power loss, they frequently lose completely unrelated data.
^this, it's amazing how few people actually understand that most writes on modern systems are buffered either in the kernel cache or in the disk cache without any form of protection. Disable those volatile caches and your OS with it's resource hog apps will behave as slowly has a 386 on floppy disks. At least, the laptop battery can act has a giant capacitor and your exposition to data loss due to power failure on a laptop should be very very small.
Judging by this, the speed is about the same as other comparable SATA III SSD's, with a little bit of a boost but nothing dramatic.
Yada yada...
10% more, 10% less, who gives a damn? Only a drooling idiot would buy an SSD because it won this month's benchmark.
Aren't we at the point where we just ignore "speed" and look at what's inside them that's going to make them last a long time and keep our data safe?
No sig today...