I want to add more RAM to my late 2008 Mac Pro - RAM is clearly my bottleneck when working with very large files.

Currently it is configured with the following:

DIMM RISER B/DIMM 1 - 1GB
DIMM RISER B/DIMM 2 - 1GB
DIMM RISER A/DIMM 1 - 2GB
DIMM RISER A/DIMM 2 - 2GB
DIMM RISER B/DIMM 3 - Empty
DIMM RISER B/DIMM 4 - Empty
DIMM RISER A/DIMM 3 - 2GB
DIMM RISER A/DIMM 4 - 2GB

TOTAL 10GB

Would appreciate some reccomendations - ta.

Edit - would it be best to ditch the 2 x 1GB in the first two Dimm slots and replace with 2 x 4GB's and another 2 x 4GB's in the empty slots? Thus giving fully matched modules for a total of 24GB?

Edit - I may have just answered my own querry - it looks like its just under a thousand US dollars to upgrade to 32 GB of RAM from OWC which maxes out the memory. Unless anyone suggest otherwise I think Ill just go this route and ditch the existing modules.

You may want to look at your scratch disk setup which could also be the cause of your bottle-necking. Save yourself some money and go with 16 gigs of ram. Invest in a fast dedicated scratch disk.

Thanks - what I ended up ordering was the 32Gig of Ram, but also a SSD for the OS and apps. Then I will rebuild my RAID 5 array onto the 3 x 500 gig drives for my image library and use the last 500 gig drive as a scratch disk.

Why not build your R-5 across all 4 drives and partition off a thin, outer slice -- say 120G -- for scratch? Or even better, partition off the outer 30G of each of the four drives and put that in R-0, then put the remaining inner 4 x 420G partitions into R-5 for storage. Either should be faster than the single drive scratch and you'll end up with more net R-5 storage...

Just a thought..,

That would indeed be faster - but part of me has never liked the idea of partitioning drives. I prefer (illogical or not) to dedicate my drives - that way I never forget what is where.

Huh? A partition behaves just like a dedicated drive. And in your R-5 scenario above, they are clearly NOT dedicated anyway -- by definition R-5 is a partition, even though it is combining multiple drives into a bigger one... As for forgetting, you can name a partition too

A dedicated scratch disk is recommended so that only the Photoshop temp files are being pushed through the hard drives pipeline. While partitioning the dedicated drive will maintain contiguous disk space, if other files reside on the same disk that need to be accessed by the operating system or Photoshop, disk speed will be degraded.

He's got the OS and apps on a dedicated SSD. So in the OP's case, having the scratch on the fast outer rim partition of the image storage array is a no-brainer for added performance over a single scratch disk...

DigLloyd recommends using a 2 partition RAID volume. For example, partition 2 drives each with a 32GB partition on the outer faster portion of each labeled as Scratch, leave the balance of the drive labeled as Data. Then RAID the Scratch volumes, and RAID the Data volumes.

http://macperformanceguide.com/Storage-RAID.html

I wonder if you could Stripe the Scratch volumes, while Mirroring the Data volumes?


But MacGurus often recommends the Scratch Disk/Work Disk method as they are reasoning that the scratch files get written right alongside the working files, so might as well be all together.

FWIW, Lloyd recommends a 2-drive R-0 scratch as a MINIMUM. He runs a 4-drive RAID-0 with a thin outer partition as dedicated scratch just like I do...

Yes you can R-0 the scratch volumes and R-0/1 the data volumes right from OSX if you want, all using the same 4 drives with appropriate partitions. You partition each drive to the first outer partition at say 30G and call it Fast-1, Fast-2, 3, 4. Then name the inner partitions Large-1, Large-2, 3, 4. Now drag Fast 1, 2, 3 and 4 into a R-0 volume and name it "Scratch". Next drag Large-1 and 2 into a R-0 volume and call it DATA, then drag Large-3 and 4 into a different R-0 volume and call it DATA mirror, now drag both DATA volumes into a new R-1 array. You set.

If you want R-5 you need a card or third party RAID software, but nowadays drives are so cheap enough that RAID 0-1 is pretty darn cost-effective not to mention efficient.

Cheers,

Thanks Jack,

I need data protection more than performance. Since I travel with my tower, so just I can't add another box of stuff to it. (can't afford any more stuff either)
Here' what I've got to work with.
MacPro with 9 GB RAM.
Drive Bay 1- Stock 250 GB
Drive Bay 2 & 3- 500GB Western Digital Caviars
Drive Bay 4- 750GB Western Digital Caviar

I was considering:
Drive #1 has just the Operating System on it.
Drives #2 & #3- Data as RAID 1
Drive #4- Scratch on an 64GB outer partition/Temporary Data Storage in the 400GB middle partition/Bootable Clone of drive #1 on 250GB inner partition.

OR
Drive #1 has just the Operating System on it.
Drives #2 & 3- Scratch on 64GB outer partition Data on 400GB inner partition, Scratch as RAID 0, Data as RAID 1
Drive #4- Temporary Data Storage on 500GB outer partition/Bootable Clone of drive #1 on 250GB inner partition.

I don't think you want to be using RAID-5 for scratch disks.

A RAID-5 configuration needs to access all drives for each read/write cycle. This means that to write 100 blocks of data to a 4 drive RAID-5 setup, you need to do 100 seek/write operations to each of the 4 drives for a total of 400 operations. In RAID-5, a little part of each of those 100 blocks is stored on each one of the 4 drives, which makes it possible to reconstruct the data if one of the drives fails.

In a RAID-0 (striped) configuration, the read/write operations (I/Os) can be done in parallel. In a 4 drive stripe/100 block write example, the system will split the writes up so that each of the 4 drives gets 25 of the blocks which are written in parallel across the drives. (i.e while drive 1 is writing block 1, drive 2 is writing block 2, etc) For a given amount of time, you can get 4 times as much data read/written as in the RAID-5 setup. In RAID-0, each one of the 100 blocks is stored on only one drive, so if that drive fails, the data isn't recoverable. You gain performance but lose reliability.

For completeness, a RAID-1 (mirrored) setup gives you data reliability at reduced write performance (you need to write each block to each of the drives in the mirror), but increased read performance (you can read a block off any of the mirrors since they are identical, so you can do multiple reads in parallel).

RAID-5 is about data reliability but you trade off performance for that reliability. RAID-0 is about favoring performance over reliability. In the case of a scratch drive, you want to favor performance, not reliability, so you don't really care if the drive crashes - it was only temporary data to start with. For your image storage, you probably want to favor reliability, although you still need good backups. RAID-1 or RAID-5 will protect you against a drive failure, but not against you accidentally deleting a file. That's what backups are for.

Martin

This is a good comparison of all RAID types and their performance:
http://www.storagereview.com/guide2000/ref...evels/comp.html

Raid 10 is probably the fastest whilst providing better data protection to raid 5 or raid1. but it requires a minimum of 4 disks.

Edit - I may have just answered my own querry - it looks like its just under a thousand US dollars to upgrade to 32 GB of RAM from OWC which maxes out the memory. Unless anyone suggest otherwise I think Ill just go this route and ditch the existing modules.
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Looking at at OWC prices, a less costly option is to keep the 2's and add 4 x 4 gig for $460.00. How much difference will another 8 gig for $440.00 make? Curious, since I basically have your current configuration.

Steve

I love OWC. I added their 32GB RAM upgrade to my 2007 MacPro 8-core. I had the OEM 1gb x 4 plus an aftermarket 2gb x 4 for a total of 12GB which I ran for a few years.

After the RAM and Snow Leopard upgrade, I used LR 2.4 to batch convert about 8,000 various vintage of Canon RAW files (10D, 20D, 1DMkII, 1DsMkII and 1DsMkIII). According to iStat Menu 2.0 (new), LR was using up to 8GB of RAM during the conversions. It all went without a hitch.

Now, I just can't wait for Adobe Creative Suite CS5 for Mac which, hopefully, will take advantage of the RAM and 64 bit OS.

Other upgrades this year include a Raptor 10krpm 360GB drive for OS and apps, 2x1.5TB internal RAID and an external eSata 5 bay tower with 4x1TB Raid5 and one drive for spare.

Cheers.
Bud

Another vote here for OWC - thats where I ordered the 32Gig of RAM for my Mac Pro month or so ago. With Snow Leopard and LR 2.4 I opened 12 Canon 1DSMK3 RAW files in LR and selected edit in CS4 and Stitch to Panorama. It used just under 29 gig of ram during the process - which ran smoothly without issue.