new iMac - picking hard drive - external or internal?

[jclin10]

Greetings


I'm looking to purchase a new 27 inch 5K iMac and am trying to make decisions about a hard drive configuration (both internal and external). I have about 1TB of home video projects and 3TB of photos, so I'd need an external drive since fusion drives only go up to 3TB. What I have in mind is to get 1TB SSD for my internal drive and then attach an external RAID configured Thunderbolt drive like this - http://www.g-technology.com/products/g-raid-tb3. It has Thunderbolt 3 and transfer rate of up to 500MB/s. Right now, I have a Thunderbolt drive that is up to 250 MB/s, but it seems like there is some lag time. I do a decent amount of photo editing and organizing and some video editing, but not much (all for personal and not professional use).


Would there be a significant performance difference between a RAID drive and the current drive that I'm using? Is there a significant difference between a SSD drive and the other 1TB drive offerings from Apple? And would there be a significant performance difference between an internal SSD and an external RAID like what I've suggested (my plan would be to keep most stuff on the external RAID unless it was a current project, in which case I would move to the internal SSD, unless, of course, the RAID offers comparable performance to the internal SSD)? Are there any highly recommended brands for RAID devices that I should consider in addition to G-Technology?


Basically, I'm trying to optimize performance without necessarily overbuying equipment and investing in more than I need to.


Thanks!
John

 

[Chancha]

I got a pretty similar use case as yours:

- Had a few external HDDs including 2 WD RAIDs
- Had a MBP and a Mini but recently purchased the iMac 5K 2017
- crap load of RAWs, taking out too much space
- LR workflow demands fast internal SSD to have catalog resides on, and then a lot of local data that I don't want to drag off the internal

So I got myself an almost maxed out 27", with 1TB SSD, and after market RAM to 40GB. Apple is using blade type SSDs with comparable performance to the Samsung 960 M.2, I BlackMagic tested my 1TB internal and got 2400MB/s read and 2000MB/s write. This is 4 or 5 times faster than Any single SSD you can plug into the iMac via TB3 or USB3.1gen2. The only way to match it is with RAID arrays of SSDs in an enclosure.

Originally I thought to keep using my older drives to see if it suffice, the WD TB1 RAID works as it did via a TB3>TB2 dongle. However, it is always 80%+ full, and speed is dragged down to 100MB/s compared to the full potential of 200MB/s+ when empty. I frequently have to move inactive stuff to the other USB single platters which is a huge hassle in data management stand point, particularly it complicates my backup strategy.

I got fed up with the situation, and seeing the G-Tech released those models that you linked, and bought myself a 8+8TB one. I have just got it yesterday and only started migrating stuff over, but so far the experience is super. The bare drives are HGST Ultrastar Helium 7200rpm, close to the best pro/consumer class drive you can get now. Being 7200rpm drives they are a bit noisy but it is acceptable, just put it away from the iMac (came with a 1m cable). The HDMI port works like a charm for my 2K 2nd display. Only real issue I have with it is the USB-C port is actually only reserved for a non-TB3 computer, I thought it would act as a hub for me, which is still good since the unit has a TB3 pass through port (so a total of 2 ports, one upstream to the Mac).

BlackMagic speed test returned a ~400MB/s read write result at RAID-0 config, which I was quite happy with (the advertised 500MB/s seems to be only available on the crazy 20/24TB models). Compared to my TB1 and USB3 drives the difference is noticeable and meaningful with moving large files/folders around. The drive wake time is also pretty short, among the fastest I have seen on this class of drives.

Having TB3 may be a waste for just 2 HDDs, but as a start of a TB3 daisy chain, this ensure I don't lose potential bandwidth, and the iMac only having 2 TB3 ports this is extra important.

 

[Trebuin]

I’m also debating the internal vs external SSD & while SATA drives are slower, if someone makes an adapter for the blade type, it would be faster...cost may make it not worth it