Fusion Drive?

It's as fast as a SSD with the space of a hard drive and twice the chance of failure of either.

 

Ssd

It is a SSD (Solid State Drive). SSD's are much faster than traditional Hard Disc drives (HDD). A Fusion drive is a SSD coupled with a HDD. The OS determines the files you use most and loads them to the SSD so that they can load faster. For example the SSD's speeds are close to 350MB/s where as the HDD's speeds are close to 50MB/s so you will be able to load files a lot faster with the SSD rather than the HDD.

 

You won't get any better performance in games or other computation-intensive applications. However, the data will probably load faster. For games this means faster level loading.

 

Any operation dependent on loading from disk will be faster. This includes loading of maps for Call of Duty. Photoshop won't be faster in every aspect, just the aspects that entail loading data from disk into RAM. If you're getting a Mac mini or a 21.5" iMac, I'd say it's a no-brainer as you'll be ofsetting the performance lag of the 5400RPM hard drive. However, if you're getting a 27" iMac, where the drive is a 7200RPM drive, it's not as important; though it's still a nice upgrade.

 

I would say that fusion drive is not worth the money it costs.
The real advantage would be to have only SSD installed, this will be possible only when SSDs of 1 TB and bigger capacity will be available at a price similar to HDDs.

 

Agreed, but Apple doesn't make it too easy for someone to upgrade the HDD after purchase.

If the cost of drives would come down for Thunderbolt or if SOMEONE would make a Thunderbolt HDD enclosure we wouldn't even need an SSD inside the iMac, we could just boot off of the external SSD and use the internal iMac HDD as a data storage device.

I am still surprised we do not have Thunderbolt enclosures yet.

 

For either 21 or 27 inch models, getting the FD is a smart thing. There is absolutely no comparison between spinning disk and ssd speeds. FD simply gives you the best of both speed and storage capacity - for the price. Once ssd capacity per dollar goes down, it's clear this will be the future, but today, the easy way of getting both is to go with a FD setup.

 

Cynical. but undoubtedly true. I have the 3TB in my new iMac, and it is considerably faster in just about everything. The "Smart" way it decides which files to cache on the SSD for faster load times is really quite clever...It takes about a week to sort itself out.

The specs on the newbie are pretty much the same as my pervious model...Maxed out 3.5GHZ with the 2GB CPU...the only difference apart from the new hardware is that this one has 32GB of RAM as opposed to the 16GB in my 2011 model. So far, nothing has failed, but I guess just stats and common sense say that if there is more to break, then more fails will occur. Apart from the well noted wake from sleep issues which seems to apply to all the new iMacs, I have been trouble free so far. I had the opportunity just before I sold my 2011 to run them side by side for about a week, and the newbie is a good 25% faster in the work I do. I'll take the chance on a fail, but so far, so good.

 

this simply isn't true. the failure rate is not double - and this has been discussed at length on other posts.

regardless, if you have ONE drive and it fails it's still a failure. you should always have a good back up regime anyway.

fusion is a great compromise until large SSDs become affordable. most naysayers on this forum don't even own fusion drives or have read the extensive ars technica post about it.

 

Of course it is, assuming the failure chance of both drives is independent from each other. Not that something like this should affect the purchase decision of an average user - sums of two zeros is still a zero

P.S. Always backup! Any data loss due to hardware failure is solely the responsibility of the user.

 

failure rate doesn't automatically double using fusion.

SSD failure rates are considerably lower than spinning platters. the spinning part of fusion is used typically a lot less than in non-fusion. non-fusion will use the HDD 100% of the time.

failure rate has so many variables associated with it (e.g. number of writes) you can't just double the failure rate.

both fusion and non-fusion have a 100% failure rate over very long periods of time - so doesn't really matter. the point is, failure rate is not a metric that should be used to decide on buying fusion drive or not.

 

Mathematically... it is not. It is not the X times the individual (and independent) failure rates. It is 1 minus the product of the individual survival rates. They are often close... but different.

So for example... if both SSDs and HDDs had identical failure rates of 30% each... then the failure rate would not be 2 * 0.3 or 60%. Instead... the survival rate of each would be 70% (1 - 0.3)... so the combined failure rate would be: 1 - (0.7 * 0.7) = 51%.

Of course, your advice to always back up is spot on... and that is true independent of risk.

/Jim

 

You are right of course. I was assuming that probability of simultaneous failure can is so slow that it can be ignored. That is:

p(failure1 OR failure2) = p(failure1) + p(failure2) - p(failure1 AND failure2)

which is essentially the formula you use. If we assume that p(failure1 AND failure2) = p(failure1) p(failure2) is very small than we can approximate the whole as:

p(failure1 OR failure2) ≅ p(failure1) + p(failure2)

In the end, it all depends on how you measure survival/failure rates. Reports I've seen suggest that modern HDDs have failure rates of 3% and less.