Scratch Disk Know How

[Bill Meyer]

I've been using photoshop for a couple years now but have never paid too much attention to "scratch disks" and am hoping that someone can help me sort this out.

I am building a new computer system and I have several options for scratch disks, but because I don't know how much the disk used for a scratch disk affects performance I'd like to hear from those of you who do know. Here are my options -

These are the disks I currently have at my disposal -


1.  Western Digital 74GB Raptor SATA w/ 8MB Buffer

2.  Western Digital 320GB SATA II w/ 16MB Buffer

3.  Western Digital 320GB SATA II w/ 16MB Buffer

4.  Hitachi T7K250 160GB SATA II w/ 8MB Buffer

5.  Western Digital 80GB IDE w/ 8MB Buffer


Here was my original plan -

Raptor 74GB as primary (C:\) drive for OS/Software
Both WD 320GB for File storage in a RAID 1 mirrored (I need data backup & protection)
Use the Hitachi 160GB as emergency data backup of primary images - (this drive will be housed in a removeable tray)
Use WD 80GB IDE drive for scratch disk

By the way, I am getting a motherboard which can take advantage of the 3Gbs of the new SATA II spec. and also will have 2GB of RAM.

So is my thinking correct, or is the scratch disk of utmost importance requiring the fastest drive available for speedier Photoshop/RAW processing applications?

Would I be better off to partition my 320GB and use a partition for the scratch disk since it is faster than the 80GB IDE drive, or would the fact that it is a partitioned drive slow it down? Thank you for your thoughts.

Bill

[Paul Sumi]

I can't speak to the relative merits of your various HDs, but if you can dedicate an entire separate drive to the PS scratch disk, that will give you the best results.

Paul

[Tim Gray]

To get the best performance from the scratch disk it should be on it's own physical drive, or at least on a partition on a drive that will not be accessed by any other application when in use (I think you've got that...)   There was a rather exhaustive discussion of pc configuration on this board recently - particularly regarding the best configuration of a scratch disk - some controversy over whether or not RAID 0 for scratch was worth it (keeping in mind that redundancy isn't an issue for a scratch disk).

I'd suggest at least considering the smaller 34? gig Raptor for the scratch disk - and nothing else on it.   I'd also consider how often you would be backing into it - ie how much ram vs the size of the files and your workflow - eg lots of layers, 16 bit panos?  If you're maxed out on ram and frequently hitting the scratch disk then a Raptor or Raid 0.

[DarkPenguin]

This seems like a good place to put this....

http://www.hothardware.com/viewarticle.asp...cleid=776&cid=4

Looks like the new Raptor is quick.  Quick enough that I might just spring for one.

[Chris_T]

I've been using photoshop for a couple years now but have never paid too much attention to "scratch disks" and am hoping that someone can help me sort this out.

I am building a new computer system and I have several options for scratch disks, but because I don't know how much the disk used for a scratch disk affects performance I'd like to hear from those of you who do know. Here are my options -

These are the disks I currently have at my disposal -
1.  Western Digital 74GB Raptor SATA w/ 8MB Buffer

2.  Western Digital 320GB SATA II w/ 16MB Buffer

3.  Western Digital 320GB SATA II w/ 16MB Buffer

4.  Hitachi T7K250 160GB SATA II w/ 8MB Buffer

5.  Western Digital 80GB IDE w/ 8MB Buffer
Here was my original plan -

Raptor 74GB as primary (C:\) drive for OS/Software
Both WD 320GB for File storage in a RAID 1 mirrored (I need data backup & protection)
Use the Hitachi 160GB as emergency data backup of primary images - (this drive will be housed in a removeable tray)
Use WD 80GB IDE drive for scratch disk

By the way, I am getting a motherboard which can take advantage of the 3Gbs of the new SATA II spec. and also will have 2GB of RAM.

So is my thinking correct, or is the scratch disk of utmost importance requiring the fastest drive available for speedier Photoshop/RAW processing applications?

Would I be better off to partition my 320GB and use a partition for the scratch disk since it is faster than the 80GB IDE drive, or would the fact that it is a partitioned drive slow it down? Thank you for your thoughts.

Bill
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I think what you are really after is how to get the best performance out of a computer to run Photoshop. Adobe actually provides many suggestions, including scratch disk allocation and then some:

[a href=\"http://www.adobe.com/support/techdocs/332271.html]http://www.adobe.com/support/techdocs/332271.html[/url]

Pay special attention to how to cache, and "Windows virtual memory and Photoshop scratch disk files". Where to allocate scratch disk space is just the tip of the iceberg. Few books, tutorials and forum discussions on scratch disk space will venture into setting up the page file(s). If the page files are not properly set up, you can't get the best performance out of the RAM size, disk speed, and scratch disk space allocation, etc.

The Adobe article is for CS2 (and I think for CS as well). While many suggestions apply to all versions, some may not be appropriate for earlier versions. As those who migrated from PS6/7 to CS/CS2 noticed, there is a significant performance degradation. Only careful tuning of the computer can reclaim some of that.

[Chris_T]

I personally would not use a RAID array. If one drive of the array dies, data recovery can be more difficult or impossible.

[Tim Gray]

I personally would not use a RAID array. If one drive of the array dies, data recovery can be more difficult or impossible.
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I'm not sure that data recovery is particularly relevant for a scratch disk.  In any event,  even without Raid 0 you're not well advised to rely on data recovery techniques to mitigate a HD failure, you need data redundancy - but you don't need Raid 1/5 to do that. I use a back up utility to keep all my data files appropriately backed up on separate drives.

As far as I can tell, the only valid reason for not using Raid 0 for a scratch disk is that the trade-off between performance and cost may be difficult to justify.  YMMV

[Jason Cory]

I'm also looking to set up a scratch disk for PS CS2. I have an almost totally empty 55gb internal hard drive I was going to use. I currently have Photoshop and a couple of other programs running off this drive, though (total space=less than 1gb).

My question is, should the scratch disk be a different drive altogether from the one I use to house PS? How will it affect performance if I use the same drive for both PS and the PS scratch disk?

[scotty]

hi,

first post. I thought i'd better try and contribute instead of just lurking.

What has worked for me ....

i recently bought (second hand from a friend in anther forum) 2x 36gig SCSI ultra 160 10k 16 meg buffer hard drives and controller+LVD.

I have put windows on one (big increase in performance over both SATA and PATA 7200rpm 9ms access time drives, now sluggish windowsxp is very snappy).

The other i have set up as my CS2 scratch drive.

My other storage drives being 760 gig of various configurations of SATA, PATA and firewire ext. and 160 gig in my server. These storage drives don't need fast access as they are not continually accessed so standard 7200rpm 9ms 8meg buffer drives are fine

There is a big difference in performance of photoshop with this setup. I only have 2gig ram in dual channel and a prescott 800mhz fsb cpu. I have allocated 70% ram to CS2. Also have double checked in the bios that the ram is running at it's maximum rated speed - you'd be surprised how many pc's i've come across that have the ram running slower than it should for one reason or another and absolutely no mixed speed ram and all Crucial Technology sticks (paired).

You can pick up SCSI kit on ebay for not a lot of cash. The kit i bought was going onto ebay and would have went for c 100 gbp (i got it for 50 gbp) which against a new cost price of 450 gbp for the lot is a remarkable saving provided you know it's all healthy stuff.

It's still not enough though  .My ideal will be more ram and a move up to ultra 360 SCSI drives at 15k rpm. Just got to keep my eye out for the bargains.

cheers.........

[jani]

I have put windows on one (big increase in performance over both SATA and PATA 7200rpm 9ms access time drives, now sluggish windowsxp is very snappy).

Not to be a big bore, but reinstalling XP on a fresh harddisk will almost certainly increase performance.

This is due to bad design decisions in Windows, which lead to poorer Windows performance over time as more and more programs are installed and uninstalled.

But of course I don't doubt that a faster disk improves performance too.

The other i have set up as my CS2 scratch drive.

It's still not enough though  .My ideal will be more ram and a move up to ultra 360 SCSI drives at 15k rpm. Just got to keep my eye out for the bargains.

Surely, you mean Ultra 320, though the difference compared to Ultra 160 is negligible for single or dual disk systems.

And to keep flogging the poor horse, try solid state solutions such as Gigabyte i-RAM for your system swap and/or PS scratch space.

Personally, I'd love it if Photoshop could run on and utilize the power of a system like the SX-5.

[scotty]

Not to be a big bore, but reinstalling XP on a fresh harddisk will almost certainly increase performance.

This is due to bad design decisions in Windows, which lead to poorer Windows performance over time as more and more programs are installed and uninstalled.

But of course I don't doubt that a faster disk improves performance too.

The other i have set up as my CS2 scratch drive.
Surely, you mean Ultra 320, though the difference compared to Ultra 160 is negligible for single or dual disk systems.

And to keep flogging the poor horse, try solid state solutions such as Gigabyte i-RAM for your system swap and/or PS scratch space.

Personally, I'd love it if Photoshop could run on and utilize the power of a system like the SX-5.
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I had a clean install 7 days before i moved to the scsi and the performance is very noticeable from that on a std ide to a scsi with access times of 3.8ms. Any way not to labour.

This machine has 8 drives in it now (4 SATA, 2 PATA and 2 SCSI) now if they + more were all ultra 320 (oops!!) and for protection in a raid setup there would be a difference between 160 and 320.

I know what you mean about the single pc std user configuration not benefiting more from ultra 320, I have a server coming with 6 scsi drives (to replace my winxp/apache pc server) but unfortunately at this stage it's only ultra 160 controller and it's embeded in the mobo  . My source is a pc recycle centre nearby...waste not want not i say...

I think suffice it to say if you have the cash then you can keep tweaking your system to squeeze the most out of photoshop until you reach the limit of photoshop itself.

In conclusion then scratch on its own fast drive (or at least a seperate partition ) well away from windows and windows virtual memory is the way to go.

[Mark D Segal]

Microsoft (Tim Grey) has published a comprehensive paper on how to optimize Windows XP operating systems for Photoshop. Useful reading. I don't have the hyperlink on hand, but you can search it on the Microsoft website.

[jani]

Microsoft (Tim Grey) has published a comprehensive paper on how to optimize Windows XP operating systems for Photoshop. Useful reading. I don't have the hyperlink on hand, but you can search it on the Microsoft website.

I don't have the link either, but if it's the article that was linked to here some time last year, I felt that it was largely fluff and not very helpful.

[Mark D Segal]

Jan, it's a very lengthy article in quite fine print, so there is alot of content. Now the extent of the content that is fluff depends on where you are starting from and what you are looking for.

One can get very deep and complex about how a Windows-based operating system and associated hardware handles imaging software - the more I read about it, the more I appreciate how the devil is in a myriad of technical details about how the O/S, processors, memory, hard-drives, graphics cards and their associated drivers work. There is no one introductory article - such as the Microsoft piece - that can cover all of this.  I think both the Adobe and the Microsoft papers provide most users with a reasonable technical foundation for equipping and specifying their computing environments to do the needful. That doesn't mean it addresses all needs and all situations.

[jani]

Jan, it's a very lengthy article in quite fine print, so there is alot of content.

Are we talking about the same Microsoft PDF?

Pixel Performance

If you're thinking about another article by the same author, then my criticism -- former and current -- is of course irrelevant.

There are too many words to help a beginner, and there are too many words to be useful to those with experience, who would benefit more from a technical document ("Pixel Performance" is not a technical document). I don't call that content; the content is hidden in the words.

There are 23 pages of document, with an astounding amount of words, to describe something which could probably be summarized in a three- or four-page document. It would make it easier for the author and technical proofreaders to spot misrepresentations or technical errors (as I pointed out the last time this document was presented here).

A three- or four-page document would also have the benefit of being quick and easy to read while still providing the pertinent information, which is what I'd consider the primary purpose of such a document.

[Mark D Segal]

Jan, it's the same paper. What makes a good paper for you at your level of knowledge may not be suitable for others. Authors of such papers write for a wide audience and some people need more explanation than others. Regardless of the verbiage, it does contain a considerable amount of useful advice.

[jani]

Jan, it's the same paper. What makes a good paper for you at your level of knowledge may not be suitable for others. Authors of such papers write for a wide audience and some people need more explanation than others. Regardless of the verbiage, it does contain a considerable amount of useful advice.

I think you missed the part where I criticized it for not being decent enough for people at another level of knowledge than my own.

In case you don't know where I'm coming from, I've been working with helping people understand texts, documentation and systems for a very long time, and in my experience, lots of text means that people get lost in the words. This is especially true for people who aren't as knowledgeable as you, Tim Grey or me.

While we can readily grasp what Tim Grey and Microsoft are trying to tell us, this is not equally true for those without that level of knowledge.

And that's where the words get in the way in the way that hurts most.

[Mark D Segal]

Jan, OK, if that's the insight from your experience with such things so be it. I can see the point you are making. I read the paper and found it pedantic in places, but still and all a useful contribution. Nothing more, nothing less. I can't get too excited about it one way or another.

[Chris_T]

Are we talking about the same Microsoft PDF?

Pixel Performance

If you're thinking about another article by the same author, then my criticism -- former and current -- is of course irrelevant.

There are too many words to help a beginner, and there are too many words to be useful to those with experience, who would benefit more from a technical document ("Pixel Performance" is not a technical document). I don't call that content; the content is hidden in the words.

There are 23 pages of document, with an astounding amount of words, to describe something which could probably be summarized in a three- or four-page document. It would make it easier for the author and technical proofreaders to spot misrepresentations or technical errors (as I pointed out the last time this document was presented here).

A three- or four-page document would also have the benefit of being quick and easy to read while still providing the pertinent information, which is what I'd consider the primary purpose of such a document.
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Jani, I was unable to either view or download from the link you provided.

For a simpler article by Adobe on the same topic, try the link I provided earlier in this thread.

[jani]

Jani, I was unable to either view or download from the link you provided.

Ah, a quotation mark had snuck its way into the end of the URL.

Try removing "%22" from the end of the URL in the address bar, or clicking on the link in the modified post.