New system drive and memory setup - please help!

Question

Please excuse these newbie questions.  I DO understand that these issues have been discussed ad nauseam in this forum.  But I have spent probably ten or twelve hours exploring the various threads, and partly owing to my ignorance, partly to the specifics of my situation, partly to the disagreements between various posters, and partly to my concern that some of the clearer statements on e.g. SSD’s may have been outdated by the progression of technology, I would greatly appreciate it if I could get some recommendations for my specific situation.
I am going to purchase an HP Z820 sometime in the near future.  I do NOT want to build my own machine; I have just enough technical knowledge to be dangerous, as they say, and want one-stop shopping for technical support if my machine develops problems.
While I will use this machine for a variety of applications, my main concern is to optimize it for Premiere Pro. Based on Harm Millaard’s (who to my untutored eye seems to be one of the most prolific, knowledgeable, and helpful individuals in this forum) “Guidelines for Disc Usage” of two years ago, I plan to install a 300GB SSD for my boot drive, and to construct a RAID 5 array out of the remaining drives. (The Z820 does not support RAID 3.) The array drives will be either five (5) more 300GB SSD’s, or four (4) 600GB 15,000 RPM SAS HDD’s.
Assume for the sake of argument that cost is not a factor, and that the 1.2TB storage offered by the 5 SSD drives in RAID 5 (vs. the 1.8TB offered by the 4 SAS drives) is perfectly adequate, which would you choose?  And why?
I should add that I am a video hobbyist, not a professional, so the outfit will receive a lot less pounding than a professional’s machine.  Thus, I don’t THINK that the theoretically more limited life span of the SSD’s should be an issue, over, say, the next 3-4 years.  (Correct me if that SHOULD be a concern.)
Re memory, I am planning on 32GB of unbuffered memory, the maximum the system will support.  I COULD get 64MB, but it would have to be registered RAM, which I understand slows things down.  The slight improvement in reliability with registered RAM is not really a concern from my hobbyist standpoint; and I think 32GB should be adequate.  I use 1080/60p footage, which of course is demanding, but don’t use a lot of special effects, or other Adobe applications for input to Premiere (aside from Photoshop, occasionally). Anyone disagree with this choice?
Finally, is there a role for a RAMdisk in this outfit, for e.g. cache files?  Would this increase the speed, or decrease the using up of write cycles on the SSD’s to a degree that would be significant for practical purposes? If so, how much RAM would you dedicate to the RAMdisk?
Again, sorry if you feel these questions have been adequately addressed in pervious threads, but try as I might I simply can’t manage to put it together on my own.  And thanks in advance for any help.

Answer 1

Pardon me for jumping in.  (I realize the question is to Harm.)
I am going to purchase an HP Z820 sometime in the near future.
Congrats, this is a great system.
... I plan to install a 300GB SSD for my boot drive, and to construct a RAID 5 array out of the remaining drives.
The 300GB SSD - is that an HP model?  If so please reconsider: it's an older Intel SSD X25-M series that is slow, and runs at SATA 3G speeds (not 6G), which doesn't do the Z820 justice.  Intel 520 series has been tested (by yours truly among others) and can be used in the Z820.
The array drives will be either five (5) more 300GB SSD’s, or four (4) 600GB 15,000 RPM SAS HDD’s.
As Harm will probably tell you: unless you also run a database server on that system, there is no advantage to 10K, 15Krpm or even SSD drives for video purposes, with the exception of possible reliability (enterprise class 10-15K drives and SSDs are tested much more extensively than desktop and nearline drives) and throughput in case of SSDs if, for instance, your workflow demands extreme bandwidth (e.g. recording of uncompressed 4K 12-bit RGB signal).
Assume for the sake of argument that cost is not a factor, and that the 1.2TB storage offered by the 5 SSD drives in RAID 5 (vs. the 1.8TB offered by the 4 SAS drives) is perfectly adequate, which would you choose?  And why?
Hypothetically, I'd choose SSDs: higher reliability, responsiveness, performance, lower power consumption.  I'd do research though to ensure they'd keep up with a lot of write I/Os thrown at them.
In reality, I'd choose neither, for reasons I mentioned above.  7200rpm nearline drives have sufficient performance for the purpose, and the capacity is much higher per dollar.
I COULD get 64MB, but it would have to be registered RAM, which I understand slows things down.
Not necessarily.  The 2% difference between ECC and non-ECC memory (negligible as it is) is not at play here because Z820 does not support non-ECC memory.  Registered or not, it has to be ECC, and registered memory is not necessarily slower than unbuffered.  Even if it was, the 2% difference is unlikely to make any perceptable dent in performance given that no editing system runs its memory at 100% bandwidth at all times.  Then again, if cost is not a factor, you could always swap unbuffered for registered later on.
Finally, is there a role for a RAMdisk in this outfit, for e.g. cache files?  Would this increase the speed, or decrease the using up of write cycles on the SSD’s to a degree that would be significant for practical purposes? If so, how much RAM would you dedicate to the RAMdisk?
For timelines with limited number of effects, I wouldn't bother, with the premise that Premiere Pro has decent memory management on its own, and that memory will serve better if just given to Premiere Pro.
If on the other hand you do start using AE heavily, you might want to dedicate a (portion of your) SSD to "global performance cache" which is a fantastic time-saving feature of AE CS6.
HTH.