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piątek, 30 sierpnia 2013

Test: Samsung 250GB SSD 840 EVO

Tags: Dell Latitude E6220, E6320 Battery , Latitude E6420 

 

The efforts to make Samsung SSDs in more frequentable TLC are not in vain . These SSD 840 EVO show that with a little common sense , you can design good products with this type of chips. What tickle the top names on the Dell Studio 1558 market, and the best perf / price ratio?

Our first test of an SSD based on memory chips TLC ( Samsung 840 ) was not conclusive. Indeed , the performance was not at the top, the life of cells inevitably called into question, and in return, the selling price at launch was not as interesting as that. Our verdict was then logic at this price, you turn in a heartbeat to the models using MLC memory chips . A few weeks ago , Samsung launched an evolution of its SSD 840 with the 840 EVO . The Dell Inspiron 1545 program always TLC memory, but many optimizations firmware and some advanced mechanisms for circumventing these defects memory chips that store three bits per cell , and are therefore slower and less enduring .

Art around the limitations of TLC ( and small counterparts ... )

In 2.5 '' 7 mm thick, the Samsung SSD 840 EVO is available in capacities of 120 , 250, 500 , 750 and 1000 GB , while the classic 840 is happy with the first three sizes. On their PCB , the Dell E4300 Battery controller used is changing. Instead of MDX which couples three ARM Cortex -R4 @ 300 MHz, the MEX used on EVO sees its operating frequency increase to 400 MHz. Also , TLC used is denser , and passes an engraving 21 nm to 19 nm. And since these chips have their doubled ( from 64 to 128 Gbps ) capacity , it says that Samsung can now climb in total storage capacity . Nothing to spoil the 3 year warranty is confirmed, and the claimed performance of the sheets have been revised up from 840. In short, you 'll understand that Samsung has put the dishes in the main to try to impose the SSD based on TLC with the 840 EVO .

If we passed the  XPS M1330test bench models 250 and 500 GB, and the performance of the latter also have their place in our ongoing comparison , we chose to focus our analysis on the 250 GB ( even if it is worse . .. ), for the simple reason that the vast majority of SSD we tested so far are of equivalent capacity. Exactly, that give the results of these tests, do you ask ? And just imagine , although they are not bad , although a relative softness in writing under the Crystal Disk Mark is a little dip in the main ranking. It is clear that the optimization of the firmware, the boost given to the controller and the XPS 1340 batteries mechanisms by Samsung are compelling, but the negative effect is felt in some tests, such as Crystal Disk Mark Specifically , we are working on blocks with 4 GB Explanations .

The brand chose to use some memory chips of 840 EVO as the SLC , and therefore are storing one bit per cell in a memory "buffer" . The amount of cells and TLC NAND flash used varies depending on the storage capacity of the 840 EVO model , and our model of 250 GB, for example, are 9GB TLC chips that are used as 3 GB of SLC chips (18 GB TLC used on the 500GB model , the 27 GB and 36 GB 750 GB 1 TB). This has the advantage of faster data writing , which first passed the SLC before then to be duplicated to the TLC . A system already seen on the SanDisk Ultra Plus as the nCache ( but MLC chips ) , which here takes the nickname TurboWrite . The results obtained by caching data on this pseudo SLC memory are obviously very good and can circumvent the shortcomings of the Dell E4310 Battery performance side TLC .

However, be aware that if - our SSD - we had to write a file larger than 3GB (which of course we tried to do ), the first 3GB of TurboWrite have well and it jumps to about 490 MB / s sequential write , then once past this stage, the write speed falls at around 250 MB / s. 's why scores reassembled in Crystal Disk Mark writing are bad enough , while on blocks of smaller size, the results are much better. At this level , our protocol clearly hampers the 840 EVO 250 GB, which does not feel the 500GB model , and for good reason , it has 6 GB TurboWrite ... Result , it appears much higher in our charts , and our protocol proves to be a much better option. Still, the 3 GB files and are rare in the daily use of a computer, so it is fashionable to take advantage of increased  HP G32 Battery performance under this limit . It's pretty weird to write, but this point of view , it would almost succeed to ignore write performance of 840 EVO 250GB under our protocol , which eventually distort things a bit . But hey, we would not repeat our protocol so as to put forward specific product from Samsung ...

Samsung plays the magicians

The other big flaw chips TLC NAND flash is of course their life . We will not repeat here you hit the lecture , but rather direct you to our review of the Samsung 840 to understand why and to what extent the TLC cells wear out faster . In this context, and as is the case on many SSD , Samsung has introduced its 840 EVO what is called the Over Provisioning . That is an area of ​​memory kept virgin, so that these cells may be sought in time to replace any dead cells , extend the  HP G4 Battery life of the SSD and keep the storage capacity initially proposed . A quick tour of the excellent management software (SSD Samsung Magician ) shows that the user retains control over this data . Base , the amount of memory reserved for the Over Provisioning is 10% , while most hard opt for 7%. But what is interesting is to choose how much memory you want to allocate for this function. Those who want to get some useful GB on their SSD can lower this value, on the contrary, those who do not want to take any chances , and do not fulfill their record, can increase the amount of Over Provisioning (which justifies all the more on an SSD -based TLC) .

Since we are in the app Samsung Magician ( version 4.2) , note that this is a small software that very well done many SSD manufacturers should follow . Very clearly, it allows a few clicks to optimize its operating system for using an SSD to check whether an update of the CD is available online to perform a secure erase its data and even start a small built-in benchmark ( which of course we prefer our usual third-party solutions ) . In addition, we note the presence of a RAPID mode function compatible with Pro 840 for example, but functional with EVO . Strange, the G6 Battery active recovery on some tests , and we realize that we have improved in performance ( even more so with the built- in benchmark Magician ) . But then , how does something akin to a " potato" mode?

After information, it appears that Samsung has developed the RAPID mode based on the available memory on the user's system . If all do not benefit to the same extent (since better to have his elbow a PC powerful enough to maximize its effects) , the RAPID mode enhances the perception of SSD performance , which will be doubled up . This mode uses 25% of available RAM and up to 1GB of RAM. Too bad, this parameter is impossible to manually edit , and holders of 16 or 32 GB of DDR3 might have liked to allocate more resources to the mechanism . That said , use the RAM as a cache to speed up some data processing is not silly and others have done this journey recently. Only real constraint , which must be borne in mind, activate the RAPID mode passes data in RAM and in case of power failure , the Pavilion G7 data will not have time to travel to the NAND flash SSD will be lost. A risk not to underestimate .

About price


Still, on the whole, Samsung book with 840 EVO SSD based TLC finally frequentable . We must now see if their prices are attractive enough to warrant our attention. They were officially launched at prices slightly lower than 840 " tout court " on the market, 840 EVO 250GB is finally around € 160 , while 840 of the same capacity is today around 145 € . It is clear that between these two models, the price difference is justified by the

HP Envy 17Tperformance and the latest firmware. But what is it facing a good MLC SSD ? A Pro 840 256GB buys new € 200 , a Corsair Neutron GTX € 210 and € 225 OCZ Vector . So, the 840 EVO TLC ultimately a good deal? Well, not necessarily if one chooses to oppose the MLC drives a less efficient but less expensive hair like Crucial M500 (140 € to 240 GB) SanDisk Ultra Plus (140 € to 256 GB ) , both based on of MLC NAND flash . And the situation is unfortunately the same for those seeking very large Latitude E5520  capacity , since the Crucial M500 960GB is around 500 € (0.52 € per GB) , while the 840 EVO 1TB is available at around 555 € (0.56 € per GB). We therefore conclude by saying that the 840 EVO is an amazing SSD in many ways that Samsung shows with him that we can offer good SSD TLC memory requirement of maximizing its firmware and develop adequate tools, but that ' choosing this type of memory , we expect the Korean manufacturer to do a little better on the price ...

 

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Czas publikacji:
piątek, 30 sierpnia 2013 11:21

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