View Full Version : Scratch speed and Ram

10-24-2006, 09:47 AM
Hey all,
System is a G5 quad with 10gb ram (even though it says 8gb in my profile). I also have a 4 disk 10k raptor raid for scratch. They are all using individual SATA ports.
My issue is I don't see much of an improvement if any in scratch speed. I work on files that are 1 - 2gb when open. When working on files I also save them to the scratch disk. I have run several benchmark test on that array and it says it fast. I limited my history pallette to 10 steps.
When I do anything like paint with a 100pixel brush, I do the motion, then wait 5 seconds for it to happen. That is true with many tools. I hear the clicking of the drive a lot when working in photoshop. BTW, it is PS2


10-24-2006, 10:08 AM
We've been kicking around CS2's need for RAM and effect of scratch over here (http://www.macgurus.com/forums/showthread.php?t=22754).

New or older style Raptor? 74GB?

If your system isn't reporting 10GB, did you do an Open Firmware reset-nvram afterwards at some point? that usually clears it up and seems nvram on G5s don't report memory correctly if you don't.

Someone else works with 1GB files and has similar complaint. I think he has Quad and 10-12GB RAM as well. But a slightly heftier scratch array, and it isn't enough.

I don't think it is worth throwing more RAM or doubling your RAID with another controller and more drives - especially if you are waiting for dual quad core Mac Pros and CS3 in another 6-9 months.

10-24-2006, 04:36 PM
Bill, several things:

1. Do you have the Bigger Tiles plugin enabled? That helps measurably with more than 1GB RAM installed.

2. Have you upgraded to CS2 9.0.1? Have you also upgraded to 9.0.2? Is the DisableVMBuffering plugin installed/enabled/disabled? The 9.0.2 update is supposed to help further with these issues. There may still be problems when using brushes with scattering and/or smoothing attributes.


What are your memory settings in Memory & Image Cache prefs?

10-25-2006, 08:03 AM
Thanks for the reply.
I have 10gb ram and it works fine. I have just upgraded since I put in my signature below.
I do plan on buying another workstation when CS3 comes out. I don't see much point until then. However I do need it now.
It also looks like I won't be able to hook up SATA to the MacPro from what the other thread said about it. I am also confused if I can do SCSI. Not sure what serial attached scsi is and the other versions.
I am not very tech savvy so SCSI is something I might just ignore.
I am upgraded to CS2 9.0.2 and I do have the Disable VM installed. however not sure how to do the bigger tile thing. or check that the disable vm is actually installed.


10-25-2006, 08:14 AM
Ok, looked for it, apparantly I have both the disablevm and the bigger tiles. They don't have the squigly line in front of them so they are installed. Maybe I am expecting too much. but I hate making a brush stroke then waiting 10 seconds for it to appear.

10-25-2006, 09:57 AM
Server Guide part 2: Affordable and Manageable Storage (http://www.anandtech.com/IT/showdoc.aspx?i=2859&p=1)

SATA versus SAS considerations... (http://forums.storagereview.net/index.php?showtopic=23633&hl=)

SATA was a step up from ATA, but seen as a "poor man's SCSI." SAS brings SCSI and SATA into a single enviornment.

When you have demanding tasks for your system, as you do, do you use 86 octane fuel? or 100 octane jet fuel?

That said, the only things holding back SATA on Mac Pro are to be expected. The G5 didn't have > 4GB memory address spaces, the Mac Pro w/ 10.4.8 does. 10.5 will make it more truly a 64-bit OS. The transition to EFI. So all the PCIe controllers are different, needed to update their firmare. And according to Barefeats, are on track to have those in place shortly, with three vendors that really need and want to get their products updated.

The switch to EFI and Mac-Intel takes time.

(I didn't realize you were talking about 10GB in your signature - not in our Quad!)

10-25-2006, 03:36 PM
Ok, looked for it, apparantly I have both the disablevm and the bigger tiles. They don't have the squigly line in front of them so they are installed. Maybe I am expecting too much. but I hate making a brush stroke then waiting 10 seconds for it to appear.

Good- glad the Bigger Tiles plugin is enabled.

But you'll probably want to disable the DisableVMBuffering Plugin. With image files that large- and 10GB of RAM installed in the machine, you should take advantage of CS2's ability to cache large amounts of scratch disk data in RAM. When this plugin is enabled however, Photoshop thinks you only have 4GB RAM installed. You'll have faster overall performance if you disable it by putting a "tilde" (~) character in front of the file name.

The image files you work with- are they TIFFs with compression? Or heavily compressed JPGs? With the exception of the Photoshop file format, compressed files add significantly to opening and saving time.


The other thing is the Raptors are optimized for sustained writes and one can really see this in a 4 x stripe of them; sustained read speeds are roughly in the middle 200's- whereas sustained write speeds are up by 400 or more.
Fast read speeds are just as important to Photoshop scratch disk performance as fast write speeds.


How do have your disks setup? What kind of Startup disk drive do you have? How many partitions or "volumes"?

You say you're working the image file from the Raptor scratch disk- are you also storing files on it?

10-25-2006, 07:49 PM
I don't have a problem with saving and opening files. That is usually pretty fast. It is just the drag of photoshop when working on files. I only work on PSD, PSB, TIFF files which are not compressed.

For my scratch I have four 74gig raptors connected individually with SATA. I use SoftRaid to stripe them.
I do not store files on the scratch. I only hold them there in the retouching phase.

Startup disk is 150gig raptor.

I have 5 250gig hitachis for backup. These are not raided.

10-26-2006, 07:31 AM
It is just the drag of photoshop when working on files

Sorry- I misunderstood. I thought you were experiencing general overall slowness including opening and saving.

With Photoshop brushes, I've found there is usually some amount of delayed on-screen rendering with any 'complicated' brushes; that is- brushes with multiple assigned brush tip attributes- especially "dual brushes", "scattering", "smoothing", and "wet edges".

This rendering delay increases with an increase in brush size and/or file size, and is more pronounced with brush strokes executed with rapid hand movements. Even 'simple' brushes at large sizes will exhibit this behavior.

But slow brush strokes- either with a mouse or tablet stylus, should have minimal or no rendering delay regardless of how 'complicated' the brush is...

Selecting 'pixel doubling' in Photoshop prefs may help a bit, but you shouldn't be seeing delays of more than a second or so.

Also- the Mac OS 10.4.8 update is supposed to help Photoshop performance significantly.

Stuff to try:

1. Did you try disabling the "DisableVMBuffering plugin"? Does that help at all?

2. I would also try to determine if your currently-installed RAM has a direct bearing on this problem by removing 6GB and re-installing only 4GB RAM. then test to see if the problem persists. Adobe's documentation on this subject implies that not all of their 'bugfix' recommendations are necessarily going to work...

I've found with my 16GB of installed RAM- there is still a penalty to Photoshop performance with smaller file sizes regardless of whether or not the DisableVMBuffering plugin is active or not. The only sure-fire way to eliminate the penalty is to downgrade back to 4GB RAM.

Of course when working larger files, this penalty is completely offset by using a fast scratch disk and allowing the system and Photoshop to cache scratch disk data in RAM by not installing or disabling the DisableVMBuffering plugin.

3. Is your current RAM installed with the largest sticks on inside slots and smaller sticks on the outside slots? That supposedly can make a difference.

4. Save a backup copy of your PS prefs, then trash the current ones.

5. Un-install CS2, then re-install.

6. How's your disk-maintenance in general? Do you regularly repair permissions, use DiskWarrior?

7. Do you have third-party plugins installed in Photoshop?

10-26-2006, 08:23 AM
I was just over on AppleInsider (http://www.appleinsider.com/article.php?id=2176) reading about Intel's November launch of the Quad-Core chips, and how quickly Apple will begin using these - and of course help for those who also want CS3 but are hesitant now.