I am about to purchase a new MacPro and want to use a separate internal scratch Disk.

1- is there much difference in performance between a 7200 and 10,000 rpm drive--the price difference is significant?

2-I have seen people using between 10 and 300 GB for this purpose. It seems that the large dics are not needed. What is the best size for just dedicating the drive to Photoshop use?

MDIJB

If I am not mistaken, 10,000 RPM speeds are only available in huge capacity hard drives. I can not imagine that you would need such a large drive capacity for a scratch drive. The optimal size of a scratch drive depends on the size of the files you routinely edit in Photoshop. I have heard from many sources that the scratch drive should be at least four or five times the size of your largest files. So even a relatively small 7200 RPM hard drive will prolly suit your purpose.

If you are really concerned about speed, you should be putting your money into more RAM. More available memory minimizes scratch drive use.

The best source of information I've seen about optimizing Photoshop on Macs is provided by Lloyd Chambers. You should check out his website, www.macperformanceguide.com, as well as his blog.

Good luck.

John

Yes, RAM first. On the other hand, a 10,000 RPM drive is much faster than a 7,200 drive. The largest performance improvement I have seen over the past few years of upgrades was a 10,000 RPM Western Digital Raptor. They are far superior to the 7,200 drives. They can be had as small as 150GB I think. If you really want to go crazy get a decent SSD for your scratch disk.

You can buy 4 640G 7200's for the price of a single 300Gig 10K drive -- and if you put those 4 7200 drives in RAID-0 it will smoke the single 10K disk on I/O... I partition off the outer 160G edge of a 4-drive RAID-0 and dedicate that for scratch. I use the rest -- over 2TB -- for working image storage and it's also very fast on reads and writes of large image files. However, since it is RAID-0 it is failure prone and needs to be backed up...

That RAID-0 will absolutely smoke a single 10,000 RPM drive, but it isn't simple and it is 4x prone to failure. Also, your hardware (mboard and enclosure) need to support more than 5 drives (RAID plus your boot). That isn't always available.

KISS--Keep It Simple Stoopid.

FWIW, with Mac OSX, RAID-0 is VERY simple to do with the built-in OS drive management software -- takes maybe a minute. And FWIW2, the Mac MB supports up to 6 SATA2 drives WITHOUT adding a card! And who cares if a scratch array fails? Just rebuild it... Stoopid

Okay, just get an OCZ Vertex SSD. Simple and even faster than RAID 0.

RAID-0 4 of those and you're really talking I/O

Add lots of ram first as others have stated, however I diverge from there, since 1998 I only use SCSI HD for the heavy stuff and the reason is simple, they are simply a lot more reliable than everything else. RAID 0 is fine but so is RAID 10. I know what so many people will say, SCSI is so much more expensive, but guess what (I KNOW I SHOULDN'T SAY IT) since 1998 I have NOT had 1 SCSI HD failure, but have had 4 IDE failures, 2 in the past year and I use a lot more SCSI drives than IDE/Serial etc. Apple IIRC used to use a lot of SCSI?

Ram is 500-2000X faster than a hard drive. How you do it, be it 64 bit OS, a ram disk, or whatever is up to you...

FWIW, Lloyd and I tested RAM discs in Leopard for scratch about a year ago and they were not as fast as our 4-drive RAID-0 on our CS benchmark test. (I have 24G of RAM in my Mac Pro.) That may have changed with Snow Leopard, so definitely worth a look. The other side of the issue is how well -- or in this case how poorly -- CS manages scratch overhead, especially for newer machines.

It is a pity that there are no 10-16Gb SSD drives. Otherwise use 4 of them in raid 0 and you have a very nice scratch disk. Combine that with 24Gb of RAM and you have a very fast solution.

My main problem is still image storage. Right now I'm using 4 640GB drives in RAID 0 (gives me around 300-400 Mbs read and write speed), which is ok but not as fast as I would wish. My dream would be 6-8 300-500 SSD Drives (that would give me a write and read speed at around 1,5 Gbs), but that dream will have to wait a bit.


One site note, the 10,000 Raptors are not really that fast anymore. Current 7,200 Harddrives are as fast when it comes to writing and reading speed.

There is a very good OCZ Vertx SSD drive that is only 30GB. MicroCenter in the US has them for $100 after rebate.

Personally, I'm waiting to see what Adobe does with CS-5 Mac and then decide what to do about scratch. If they code it to actually utilize installed, available RAM, then scratch becomes almost unnecessary except perhaps for very large, layered files. And with some wishful thinking here, utilizing a fast OS array may be adequate. Worst case would be the same solution I am currently using -- the thin outer rim partition of a 4-drive stripe for scratch and the remaining for working image storage. Regardless, I may move my OS from its current 2-drive RAID-0 array to a single really fast SSD, or if they get cheap enough, a pair of smaller fast ones -- 64G x 2 is plenty -- in RAID-0.

If money were no object, I'd have OS on a 2x64G Intel X25E SSD R-0, scratch on a dedicated 4x32G Intel X25E SSD R-0, and image storage on a separate 4x256G Crucial SSD R-0 array. Of course that is like $5,000 in SSD drives, which is not out of the question for some, but still seems a bit extravagant for me. Maybe if I get a good bonus this year LOLOL!

If you get that bonus, you can slip me a few X25s too.

I'd like to point out that a SSD isn't *exactly* the same as a DDR-based ram disk. But DDR ram disks are *really* expensive. OTOH, if you have 16GB or more, you can do nicely with a good 64 bit OS in a pinch. You'll also have to move the swap file if you're using Windows, as well as the temp and swap directories for Photoshop/etc to the thing or you'll not see most of the benefit.

Yes, they cleaned up the 64 bit code in Snow. Very slick now, as it should be.

Heck, I am such a gear slut I may fold and do it regardless of bonus -- but either way, you are on your own for obtaining your SSD's LOLOLOLOLOLOL!!!