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Is flash memory better than a hard drive?

I noticed the new Macbook Pro with Retina display has flash memory instead of a Hard drive. I love the new features and I want to buy it but I'm very skeptical of this flash memory. Can someone please help explain it to me. Is it better than have a hard drive in your computer?

MacBook Pro with Retina display

Posted on Jun 18, 2012 7:45 AM

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Posted on Jun 18, 2012 7:50 AM

Flash memory is the same technology as used in flash drives, mobile devices, memory cards, etc. It has becomve very reliable, is very, very fast, but expensive compared to hard drives. That is the biggest reason for such smaller storage offered in the form of flash drives.


It has an advantage in that there is no disk to get damaged from a moving tracker arm, no motion sensor is needed to lock the track arm.


With the new systems, the flash memory offers extremely fast startup and retrieval of apps/data from the internal storage.

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Jun 18, 2012 7:50 AM in response to abc123katie280

Flash memory is the same technology as used in flash drives, mobile devices, memory cards, etc. It has becomve very reliable, is very, very fast, but expensive compared to hard drives. That is the biggest reason for such smaller storage offered in the form of flash drives.


It has an advantage in that there is no disk to get damaged from a moving tracker arm, no motion sensor is needed to lock the track arm.


With the new systems, the flash memory offers extremely fast startup and retrieval of apps/data from the internal storage.

Jun 18, 2012 8:13 AM in response to abc123katie280

Google a site that specializes in reviewing SSD


Also why they are used - low power (next to 2W I guess), therefore little to no heat to put into a laptop, and no noise.


Cost: well seeing how a 1TB WD Black (desktop not laptop) is the same price range ($120) as some 128GB SSD (yes, 1/10th the size) but 128GB is actually more than enough for an operating system.


A combination of both works best: OS on SSD and data on 500-2TB hard drive.


SSDs are into their 3rd generation at least and while 2011 was rough on SSD firmware, was rough for Apple MBPro SATA3 design problems... the technology continues to improve and mature.


A 256GB SSD Crucial m4 was briefly Memorial Day sale $180. Large enough for most and about what a hard drive replacement or upgrade might cost (put the old drive in a 2.5" external case).

Jun 18, 2012 8:25 AM in response to abc123katie280

If you compare let's say 2 MB Pro's.


One using a conventional Hard Drive and the other using a Flash Drive/SSD.


The one with the Flash Drive will seem to perform faster.


Flash Drive/SSD have no moving parts, which is why it's faster. No read and write head moving in and out to look for your files.


As the Hatter has mentioned, it does save on energy when you're using your MB Pro on batteries..


Do you really need a MB Pro - Retina? You can also get a MB Air if you wish. That too comes with a built in Flash Drive. Keep in mind however, since Flash Drives in both MB Air and MB Pro - Retina are non-user upgradeable, it's best to get the largest one available for your MB.


Another option, buy a MB Pro ( non retina ) and get an SSD drive installed after. That way, not only do you have an SSD in your MB Pro, you can use the original drive that came with your MB-Pro as a back up drive.

Jun 18, 2012 10:20 AM in response to abc123katie280

..I'm very skeptical of this flash memory...

Me too. While the flash memory is way ahead of a HD in speed, ruggedness, size, etc., each memory cell has a finite life based on the number of times it's been written to, unlike a HD, where the same sector can be written to over and over without ill effect. A variety of methods are used to insure that all the activity isn't concentrated in a small portion of the available memory cells (i.e., wear leveling), which I've been slowly researching, but I'd like to hear from the experts whether, by virtue of that, flash memory can be expected to outlive the computer it's installed in, or if it's an unacknowledged weak spot.

Jun 18, 2012 10:32 AM in response to FatMac-MacPro

In the past, or more accuratley the early days of flash memory, repeated access was a limiting problem. Flash memory has progressed markedly since those days. The quoted Mean-Time between Failurs for flash memory is now on a par with traditional storage. That gives one confidence in the longevity of SSD.


I would disagree with your assessment that the HDD platter can be written to repeatedly without failure...all magnetic media will degrade with usage. Whether tape or platter, or anything else...writing/erasing/writing degrades the magnetic medium. A platter has the additiona failure mechanism of read/write head contact or impact. That is truely non-repairable damage.


Anyway, when one wants to consider SSD vs HDD the questions of longevity should be less important than those related to cost vs needed space. SSD is still a very expensive option, but a very fast responding option.

Jun 18, 2012 10:35 AM in response to FatMac-MacPro

FatMac\>MacPro wrote:

...each memory cell has a finite life based on the number of times it's been written to, unlike a HD, where the same sector can be written to over and over without ill effect. A variety of methods are used to insure that all the activity isn't concentrated in a small portion of the available memory cells (i.e., wear leveling), which I've been slowly researching, but I'd like to hear from the experts whether, by virtue of that, flash memory can be expected to outlive the computer it's installed in, or if it's an unacknowledged weak spot.

It has been said that the memory cell management has reached the point where most people are going to want to upgrade before they hit the end of life of the cells.

There are the academic and practical sides to this. The academic side says the memory cell life is a flaw compared to spinning disks. The practical side says you should be replacing your spinning disks after a few years anyway, before they inevitably fail. The practical side says in the end both choices are about the same.

Jun 18, 2012 10:52 AM in response to Network 23

Network 23 wrote:


It has been said that the memory cell management has reached the point where most people are going to want to upgrade before they hit the end of life of the cells.

There are the academic and practical sides to this. The academic side says the memory cell life is a flaw compared to spinning disks. The practical side says you should be replacing your spinning disks after a few years anyway, before they inevitably fail. The practical side says in the end both choices are about the same.

Since neither HD nor flash can be expected to live forever, anymore than the computer either is in can, my concern has been that flash media would last longer than the computer's compatibility with Apple's OS upgrade cycle (e.g., my Mac Pro 1,1 won't do Mountain Lion). While I agree with Ralph Landry1 that HD's are physically much more vulnerable than flash (why I called flash more rugged) and that recording sites on a platter must eventually degrade, memory cell management never seemed to be an issue with HD's that needed to be addressed, hence my question.


The 3 year warranty is certainly a solution, but my computers and hard disks have lasted a lot longer than that. And if Apple wants $500 just to go from 512GB to 768GB, what must the full cost of a 768GB drive be? Of course, in three years time, the cost will have likely plummeted, just like RAM prices, but maybe not so much, being a proprietary component rather than an industry standard configuration.

Jun 18, 2012 8:06 PM in response to FatMac-MacPro

FatMac\>MacPro wrote:

And if Apple wants $500 just to go from 512GB to 768GB, what must the full cost of a 768GB drive be?

I had that same question and looked up some SSD prices at macsales.com and amazon.com 480GB-512GB SSDs are $412-$2000 depending on the performance level. I only found one close to 768MB and it was over $2000. Not sure where Apple is getting theirs...maybe they're using space in the case to gang up less expensive smaller capacity drive modules?


The real cost to me is that the entry level's 256GB is just not enough so I would have to pay the extra $500 to go to the next model. I wish the entry level SSD was configurable.

Jun 19, 2012 10:29 AM in response to Network 23

Network 23 wrote:

It has been said that the memory cell management has reached the point where most people are going to want to upgrade before they hit the end of life of the cells...

There may also be an issue of how the flash drive is used. If I were to move my current boot disk's contents to the 768GB flash drive option, it'd be close to 90% full. Clearly, if the 10% free space is what gets hit with most of the writes, it's going to wear out a lot faster. If I understand wear leveling correctly, largely stationary data will periodically be written to the most used space on the drive and the space left behind erased and allowed to get some wear to even things out. But I imagine that would be more frequent if there wasn't much free space to begin with.

Aug 3, 2012 11:09 PM in response to abc123katie280

I just bought yesterday the 15.4 in with the Retina display with the 256 flash drive. It is amazingly fast. It will open from the time you press the on key in less than 7 seconds. I have been using a PC with Windows since the mid 90s and I can already, with the help of Google, get around in it with no problems. I am a photographer and have over 75,000 photos on an external and it opened them in Picasa in no time. And my CS6 speed just puts a smile on my face. I purchased mine for $2089 and it is worth every penny. Im also a nurse and just with the time Im saving on this machine it will pay for itself in a month because I have extra time to work overtime. It is also so light weight that you can hold it in the palm of one hand, if needed. Go to the apple website and look at the samples of the Retina sreen. I watched a disney movie on it and it was more 3D than 3D movies I have paid to go see in the theatre.

Aug 3, 2012 11:33 PM in response to abc123katie280

Everything about the Retina MBP is brand new... not just the Flash drive. That means that these machines can be a little buggy for early adopters, and it will probably be a year or two before they're 100% reliable.


If I were on the market to buy a new MBP this year, of course I'd get the Retina. And a bottle of aspirin. And some stomach antacid. And I'd be looking for numbers and places to go for warranty repairs. But I'd have this cool laptop, too.


Most of the Retina MBP features will be more standard, and more reliable, as time passes. The Flash drive is fast. Really fast. Faster than the old fashioned hard drives. And it has no moving parts, which is supposed to help the computer stay more reliable. Because everything in the Retina is glued in place though, it has to stay reliable because they can't really be repaired easily if something goes wrong.


I guess I'd say that, if you have extra money to experiment with something new, it's a cool purchase. If you need a reliable computer that runs day after day without too many problems, be careful.

Aug 4, 2012 10:39 AM in response to alwaysforever

A very sensible post. Yes, I think the Retina is for early adopters with money. I cringe watching college students and "I'm on a budget" posters trying to justify a Retina. Don't worry about it! Get a cheaper, more conventional laptop now. Even I would currently prefer a non-Retina because it is upgradable in the future (you can give it an SSD too, now or later) and has more ports that I actually do use. And with the non-Retina model it is possible to have a second drive by swapping out the optical bay.


If you must have a Retina but have limited funds, wait a year or two as its features become, as alwaysforever said, more standard, more reliable, and to add to that, less expensive.

alwaysforever wrote:


Everything about the Retina MBP is brand new... not just the Flash drive. That means that these machines can be a little buggy for early adopters, and it will probably be a year or two before they're 100% reliable...Most of the Retina MBP features will be more standard, and more reliable, as time passes.


I guess I'd say that, if you have extra money to experiment with something new, it's a cool purchase. If you need a reliable computer that runs day after day without too many problems, be careful.

Aug 12, 2012 3:12 AM in response to FatMac-MacPro

Some could say that reliability of SSDs is less than magnetic HDs but that is debatable. First, is the number of write cycles - or truly sector-erase cycles, in the case of flash memory because erasing a sector is when danage can be done to the memory. SSDs can usually do 100,000 erase cycles (at room temperature) before excessively slowing down, which equates to 300 years writing to each disk sector once a day, this reduces to 10,000 cycles at high temperatures (usually internal temperature of 85°C) but still this is 30 years at one erase per sector per day. This is nothing compared with HDs which can do approximately 1,000,000 write cycles, hence why some say they don't degrade. Obviously they do; a well used HD could start having block failures after five years and it is common for the control hardware to fail before the magnetic disk!

What is more interesting is shelf life. A hard disk could probably survive 30 years or more in cold storage, but eventually the magnetic coating of the platters will degrade, losing their magnetism and the data with it. Conversely, the floating gates in flash memory could hold their charge indefinitely, in theory. That's forever folks! Plenty long enough for anyone! I say in theory because we're now entering the world of quantum mechanics where there is a small possibility that the electrons in the charge "exist" outside of the floating gates and therefore could leak out eventually. However this probability is so small - and the number electrons so large - that leaking the odd electron over millennia would have no noticeable affect. The disks will be long lost and buried by the time the data are lost! Panic over!

The third thing to note is the problem of rapidly changing data. Most rapidly changing data resides in RAM of course. But caches, such as RAM disks (a file on disk that acts like RAM) or virtual memory (a cache that is used to extend the size of RAM that programs believe they have access to, used to swap pages in and out of RAM, which is why it's also referred to as a swap file), have far more writes than once per day. These are typically the areas that wear out first, explaining why HD life expectancies reduce from 3,000 years to 5! Flash memories have a cunning plan so that these areas of memory don't die in six months: they swap sectors around. For each sector a sector erasure count is recorded. The flash controller should pick the next empty (or marked for erasure) sector with the lowest erasure count to write to. For example, if a cache occupies just one sector and there are 100 sectors free on the disk, the controller should ensure that each sector is used equally, thereby reducing the wear on each by a factor of 100. So, if the cache is written to 100 times a day the life expectancy of these sectors would still be 300 years. If the access rate is higher the life expectancy decreases; 1000 times a day is 30 years, 10,000 is 3 years and so forth. But what typically happens on a hard disk is one set of sectors gets written to and never changes while another set is constantly changing. HDs just keep the unchanging block in the same location because they are so slow (unless you defragment the disk, which may move permanent blocks of memory) whereas SSDs can swap around unchanging sectors with rapidly changing ones. For example (note I do not know the actual algorithms but this will serve as an example) if the controller realises one sector has been erased 100 times but it knows there are plenty of sectors that have never been erased - that hold "permanent" data - it can erase the overused sector, copy the data from the underused sector, erase that and now a sector with an erase count of just 1 is available for a cache. By recycling sectors that contain "permanent" data the wear of the SSD can be evenly spread reducing the average sector erasure rate back down to 1 erase per day and increasing the life expectancy to 300 years! So, all things being equal - which as I have shown they are definitely not - SSDs are probably more robust and reliable than magnetic HDs. Remember: don't panic! Usually some bright engineer has worked out the problems and implemented solutions before you even knew they existed; new technology is real progress rather than change for change's sake. (Unlike politicians...)

Is flash memory better than a hard drive?

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