Dear all,
I am still hesitating between a 21,5 or 27 inch. If I take the fusion drive on the 21,5 will it be a 5400 or 7200rpm hard drive ?
Thanks !
If all the standard drives in the 27" are already 7200, why would they down speed the fusion to what the 21" comes with?
The 21.5" has a 2.5" hard drive - 5400rpm 1TB 2.5" drives have very high data density per platter, so the speed difference shouldn't be significant compared to a 1TB 3.5" 7200rpm drive.
Most of the larger drives on the market are 5400 rpm.
Also, the fusion drive is probably 5400rpm to save power - it seems to be the default option apple use.
I don't know for sure, this is just speculation, but....
I doubt that the rpm difference will make much real world difference anyway, 128gb of cache is HEAPS for caching hot data, all writes are cached and serialized in SSD first, so they only time the rpm difference will make any real performance impact is if you are performing a lot of random reads on non-sequential data, that you don't frequently access, and were written a long time ago.
Fusion drive only uses 4gb for "caching" hot data" If you copy a file larger then 4gb you may notice the performance decrease as it starts to write to the regular hdd or offload data from the 4gb ssd cache to the hdd. In practice 4gb's is actually a very large amount and most users should not be able to tell the difference in everyday usage.
Totally untrue - the Fusion Drive always holds 4GB in reserve on the SSD for performance reasons (SSDs don't like to be completely full). You seem to have confused this with caching, but Fusion Drive isn't really a caching system, regardless. All writes go to the SSD and are then moved to the HDD if they aren't accessed frequently. In practice, you can write data to the Fusion Drive at SSD speeds until it fills up; not sure if it stops 4GB short of completely full, or more than that - Macworld did a test on the mini that says "up to 100GB", but that seems to be data on top of the standard OS + Apps install.
According to this site:
http://www.macworld.com/article/2017365/lab-tests-pushing-a-fusion-drive-to-its-limits.html
The mechanical portion is 5400 RPM.
...
Macworld was testing the fusion drive in a Mac Mini. Mac Mini uses 5400 RPM HDDs, so it's no surprise that the fusion drive uses the same.
The unknown is the fusion drive in the 27" iMac. This system uses 7200 RPM HDDs, and it would be perfectly reasonable to stay with 7200 RPM for fusion in this system. Or they could go cheaper/cooler/quieter with 5400 RPM.
Basically I could upgrade to SSD or BUY A SECOND iMAC!! That's crazy.
How come we cant know more specific whats in iMac ?
Why dont they have a full specification?
Do we really need to spend alot of money and open it ourself to find out what we bought ?
I would really want to know if its a 5400 or a 7200rpm on the 27".
Being a 5400rpm we would spend way more whats it worth for a 128gb ssd
All 21-in models have a 2.5-in 5400rpm 1TB HDD, all 27-in models (except the SSD-only version) have a 3.5-in 7200rpm HDD that is either 1TB or 3TB.
All models except the low-end 21-in have a blade slot for the SSD component of the Fusion drive.