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Topic : "PS scratch disk/ optimization" |
trurl
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 Posted: Wed May 11, 2005 11:31 pm |
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Sorry in advance for the hundred and eleventeenth version of this thread - rather than waste time digging i thought i might get the stripped down version from a trusted source[s]. Feel free to refer me to existing threads on the topic.
1. I have a new machine with 2G ram and all 7200drives. OS is on one drive and I have a seperate work drive. Which drive should I put a dedicated scratch disk partition on? Is it pointless to have the scratch partition on the same physical drive that you are working on - I mean are they spinning at the same time therefore the scratch should be on a different physical drive than the work drive for better performance? Is anyone using multiple scratch setups - if so what do they look like?
2. How should paging file size and any other OS related settings look?
I'm running XP Pro and not RAID enabled. Any and all optimization info greatly appreciated..
thanks |
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cheney
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| Posted: Thu May 12, 2005 3:40 am |
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First describe your typical PSD to me. Are you heavy into painting or filtering textures that take up the entire canvas? Do you usually make several texture layers in a single PSD. What pixel dimensions do you typically work at?
Let me describe some of my PSDs created from Photoshop7:
1) A PSD file containing thousands of layers where each layer contains extremely small amounts of information. The canvas size of this image is around 800x600px. This PSD saves at about 65mb, but uses about 750mb of scratch disk.
2) A PSD file containing about 20 layers where each layer contains large texture data that takes up the entire canvas. The canvas size is 6000x9000px. The PSD saves at just over 2gb, but consumes more than 40gb when open.
Now let me explain ram and scratch disk a bit:
By default the first scratch disk location is memory before harddisk and this cannot be changed except for the amount of memory used. Then photoshop will use a harddrive as data overflow from ram in exactly the same manner as Windows writes its page file. If the primary harddisk location fills with from writing scratch disk information than a second harddisk location will be used.
The speed of your hardware is everything. By speed I am mostly talking about ram frequency, bus speed, and the RPM of your harddisks. The limiting factor is scratch disk cache levels. The more locations the scratch disk has to write to the slower it will be.
Here are two ideal setups that I have imagined so far:
1) SCSI Raid1 - In this setup you will be using an array of 15000rpm drives in raid setup designed only for speed with no consideration for backup or security. In this setup you can work with file sizes as large as you want without a decrease in scratch disk read times. If you run out of room then merely add a new harddisk to the array. You will always be limited to a maximum speed allowed by the SCSI configuration such as a theoretical 320mbps if you have a great many drives in your scsi array on a single channel, but file size limits reach hundreds of gigabytes or terabytes.
2) Ram Disk - In this setup you will have a large hardware supply of ram installed on the motherboard even if the OS cannot use it. The idea here is to set a file system into the ram not used as OS memory. RAM is always going to be 10-20x faster than the fastest harddrive configuration. If your scratch disk consumption is likely to never exceed 10-15gb and you have lots of money then your best option is to max out the memory slots in your motherboard with the largest ram chips allowed by your motherboard. If you have a 10gb ram disk you will always be able to access your scratch disk info faster than the SCSI option mentioned earlier, but this slows based upon how much data overflows your ramdisk to your harddisk.
As far as page file is concerned:
I too have 2gb of RAM. I completely turned my page file off. I don't need it and I don't need it written to. Every time I open Photoshop I get an error warning about my page file, but I notice no difference in performance with it off. If you have 256mb set for your graphics aperature set in your bios then you probably only really have 1777mb of memory free for software use. I typically give photoshop 80-85% of this so that other applications can still have memory to use.
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eyewoo
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| Posted: Thu May 12, 2005 7:18 am |
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cheney ... I've also noticed that with 2 gig of RAM, if I allow Photoshop to most of it, like 96%, the scratch disk swapping slows down dramatically. If I cut Photoshop back to 80%, the scratch disk speed is dramatically improved. Any idea why that is...
Since I use few other applications when using Photoshop, I figured I may as well give it as much RAM as possible... Apparently that is not proper figuring...
Using a laptop with one hardrive, with a large partition and a smaller 5 gig partition used for PShop's scratch disk. WinXP home edition.
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trurl
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| Posted: Thu May 12, 2005 9:47 am |
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i'm running CS - heavy into painting typically at +/- 3K with 5-15 layers. for me it's all about brushes and level adjustments. little or no filtering. i don't have RAID capability. i have 3.4GhzP4, 7200rpm drives and 2G ram.
i just want to know where to put my scratch disk and how big to make it - and if i need to do anything with the paging file size. what's the consensus on the best setup given my current hardware for PS performance? |
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trurl
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| Posted: Thu May 12, 2005 11:14 am |
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| nevermind guys - i just didn't a forum search for this topic and turned up dozens of related threads.. thanks though. |
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B0b
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| Posted: Thu May 12, 2005 2:03 pm |
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there's a CS Scratch Disk Space Fix on Adobes site to stop it using so much HDD  |
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B0b
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| Posted: Thu May 12, 2005 2:08 pm |
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| cheney wrote: |
As far as page file is concerned:
I too have 2gb of RAM. I completely turned my page file off. I don't need it and I don't need it written to. Every time I open Photoshop I get an error warning about my page file, but I notice no difference in performance with it off. If you have 256mb set for your graphics aperature set in your bios then you probably only really have 1777mb of memory free for software use. I typically give photoshop 80-85% of this so that other applications can still have memory to use. |
arg! minimum pagefile needed by windows is the same as ur physical RAM, or u will see a performance lag..
i used to think the same as you, so i turned my pagefile off, but had performance problems when switching apps etc..
my m8 who is sys admin for a large company (400+ users) told me what my problem was, winblows kernal needs pagefile, and as soon as i set my page back to 2GB my machine was back to speed
256MB Apatrure for your Graphics Card is only needed if you are using your machine for Games/3D modeling and want the max 3D performance out of your 256MB Graphics Card |
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B0b
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| Posted: Thu May 12, 2005 2:13 pm |
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| trurl wrote: |
1. I have a new machine with 2G ram and all 7200drives. OS is on one drive and I have a seperate work drive. Which drive should I put a dedicated scratch disk partition on? Is it pointless to have the scratch partition on the same physical drive that you are working on - I mean are they spinning at the same time therefore the scratch should be on a different physical drive than the work drive for better performance? Is anyone using multiple scratch setups - if so what do they look like?
2. How should paging file size and any other OS related settings look?
I'm running XP Pro and not RAID enabled. Any and all optimization info greatly appreciated..
thanks |
i have a RAID 0 PATA setup on my workstation, my scratch is partitioned straight after my System Partition (2nd fastest place on the platter)
idealy Scratch should be on a seperate HDD to your system, but i don't really notice any problems with it writing to my scratch.. i'm getting another couple of HDD to RAID soon (damn all the photos i keep taking) so i'll prolly put my scratch as the first partion on those |
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trurl
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| Posted: Thu May 12, 2005 3:13 pm |
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thanks.
so would there be an appreciable performance lag if i partition my work drive [not the drive with my OS on it] and make it a +/-10G scratch disk? i mean does the scratch really NEED to be on a different physical drive than the drive with the PSD files you are working on? |
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B0b
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| Posted: Fri May 13, 2005 10:01 am |
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| if you don't have a seperate partion for scratch, then it will become fragmented as you and windows/Mac OS moves files about, a heavily fragmented swap file will slow you down |
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cheney
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| Posted: Sat May 21, 2005 3:16 pm |
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| eyewoo wrote: |
cheney ... I've also noticed that with 2 gig of RAM, if I allow Photoshop to most of it, like 96%, the scratch disk swapping slows down dramatically. If I cut Photoshop back to 80%, the scratch disk speed is dramatically improved. Any idea why that is...
Since I use few other applications when using Photoshop, I figured I may as well give it as much RAM as possible... Apparently that is not proper figuring...
Using a laptop with one hardrive, with a large partition and a smaller 5 gig partition used for PShop's scratch disk. WinXP home edition. |
Not exactly sure why that is, but I can guess. It would help me to guess more accurately if I knew what your hard drive setup was like as far as speed, type, and available space.
My guess is that you are using somewhere between 2-3gb of total scratch disk space. If this is true then you are using only a bit more that what you can fit into your RAM space. This would mean the majority of the data is contained in RAM and only a small amount over flows to the primary scratch disk. The result is that your CPUs would have to work harder to deceide what parts of the data should be in RAM. When the RAM space is larger you now have more data that can be written into this space, and this means more data that must be swapped if access is required to that little bit of overflow. When you set your memory to the lesser 80% there is less space to manage, and your computer will swap data more often but in small and less noticable incriments.
Sorry, but that is my shot in the dark theory off the top of my head. What I said makes sense as a rational answer to your problem, but I just cannot believe I have never thought of this before myself. I will have to test this later and see if my computer works in a similar manner. Our hardware is nearly identical, so I will expect similar results.
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B0b
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| Posted: Sun May 22, 2005 5:21 am |
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| any1 noticed that if you have less swap than RAM PS has a paddy? (noticed this in 6.5 when i was setting up a machine, and i put 6MB instead of GB for scratch when partitioning on a Mac 1 time, set the 6MB and restarted PS, only to find it refused to run.. |
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eyewoo
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| Posted: Sun May 22, 2005 8:58 am |
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cheney... I'm using a 5 gig separate partion for the scratch disk and, with 2 gig of ram, have actually run out of scratch disk space with some images. I work on some pretty big files. I may need to increase the scratch disk partion to 10 gig.
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B0b
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eyewoo
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trurl
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| Posted: Sun May 22, 2005 10:31 pm |
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| Quote: |
| Note that overall performance may be reduced for users with multiple processors or more than 1 gigabyte of RAM. |
that's what adobe had to say. anybody with 2G ram have any problems with this plug-in? i don't want to install it if it just causes other problems. |
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B0b
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| Posted: Mon May 23, 2005 1:25 am |
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only notice in performance i noticed was it freed up gigs of my scratch
i'm off of CS:1 now anyway.. |
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eyewoo
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