CS5 scratch disk, usb2 or FW800?

Hi,

I have a 27" iMac with 8GB ram, it has a 1TB hard drive which I am currently using as the PS CS5 scratch disk, I've read it's best to have your scratch disk separate from you main hard disk, so I'm thinking of buying an external drive to use as a scratch disk.

I want to use 2.5" drive as I don't want an extra power cable, will I notice any difference in performance using FW800 drive over a USB 2 one? USB ones seem much cheaper, but I don't mind paying for a FW800 one if needed.

Also, will a 2.5" drive be a problem? as 3.5" drives can have faster drives in them (?)

I don't mind paying the extra ££ per GB for a portable drive it if means I don't need another mains cable.

Also would it be OK to use the scratch disk for time machine back ups as well? I would not run any TM backups while using PS.

Thanks for reading,

--
Julie

Julie Sinar said:

I have a 27" iMac with 8GB ram, it has a 1TB hard drive which I am currently using as the PS CS5 scratch disk, I've read it's best to have your scratch disk separate from you main hard disk, so I'm thinking of buying an external drive to use as a scratch disk.

Click to expand...

It's best to have it separate, but you probably won't notice much of a difference unless you are pushing CS5 really hard and editing very large images. With 8 gig of memory in the iMac, the need for scratch space is minimal.

Julie Sinar said:

I want to use 2.5" drive as I don't want an extra power cable, will I notice any difference in performance using FW800 drive over a USB 2 one? USB ones seem much cheaper, but I don't mind paying for a FW800 one if needed.

Click to expand...

FireWire 800 is significantly faster and can provide more than enough power to run a portable drive. With USB, you may still need a power adapter (or a dual USB cable), depending on the computer.

Julie Sinar said:

Also, will a 2.5" drive be a problem? as 3.5" drives can have faster drives in them (?)

Click to expand...

2.5" drives are generally slower than 3.5" drives.

Julie Sinar said:

I don't mind paying the extra ££ per GB for a portable drive it if means I don't need another mains cable.

Click to expand...

That's a big advantage with portable drives. However, unless you are going to be traveling with it, it's a lot less expensive to get a 3.5" drive for the same amount of storage.

Julie Sinar said:

Also would it be OK to use the scratch disk for time machine back ups as well? I would not run any TM backups while using PS.

Click to expand...

It will work, but it's not a good idea at all.

Buy a 3.5" drive for Time Machine, hook it up and forget it's even there, until it's needed. I would also suggest that you get more than one drive for backups and put at least one of them off site. Cloning your main drive with SuperDuper works well for off site backups (or on site too).

Julie Sinar said:

I want to use 2.5" drive as I don't want an extra power cable, will I notice any difference in performance using FW800 drive over a USB 2 one? USB ones seem much cheaper, but I don't mind paying for a FW800 one if needed.

Click to expand...

A scratch disk is used to supplement RAM. Nothing is as fast as RAM. That means, if your goal is to be comparable to RAM, since no hard drive is as fast as RAM, you ideally want the fastest drive you can get. A USB 2.0 drive makes for a slow scratch drive. FireWire 800 would be much better. I recommend one of these, which have USB, FireWire, etc. ports on the back:
http://eshop.macsales.com/shop/firewire/EliteALmini/eSATA_FW800_FW400_USB

If you really want a good scratch disk to come out of that:

• Get the 7200RPM drive option (actually, SSD is vastly faster and would be the very best choice, but the problem is it's vastly expensive)
• Hook it up with FireWire 800

The great thing about those drives is that you need no mains cable whether it's plugged in by the USB 2.0 or FireWire cable. I think they still include one, but I never, ever need to use it with any Mac I have, including my laptops. I have a box full of the unused power adapters for those drives.

Julie Sinar said:

Also, will a 2.5" drive be a problem? as 3.5" drives can have faster drives in them

Click to expand...

You can use either size. I think it's going to come down to what your bottleneck is. If you use USB 2.0, it isn't going to matter what drive you use...all drives will be bottlenecked by how slow USB 2.0 is, in other words even the slowest 2.5" drive would be way faster than USB 2.0. Now while a 3.5" could potentially be faster, to take full advantage of it you want to use FireWire 800 and unfortunately you'd definitely need a mains cable for it at all times.

Julie Sinar said:

Also would it be OK to use the scratch disk for time machine back ups as well? I would not run any TM backups while using PS.

Click to expand...

The problem with Time Machine backups is that they slowly grow until they take over the whole disk. You could use one disk for both, but I would suggest partitioning it into two volumes. Maybe 60GB (really wild guess there) for a scratch volume and the rest for Time Machine.

Thanks for the information.

I did not think I would need a scratch disk, having 8GB of ram, but while I was putting together a Pano my efficiency went down to 30%, so I think I really need to get one, even just doing regular editing I often drop down to 80% efficiency.

I do back up a lot, I back up to 3 separate hard drives, and keep one at my parents house, so back ups are not an issue. I don't keep them plugged in all the time though, as they a 3.5" drives, and I don't like the noise they make, I find it distracting.

--
Julie

Julie Sinar said:

I did not think I would need a scratch disk, having 8GB of ram, but while I was putting together a Pano my efficiency went down

Click to expand...

I just tried a pano and while Efficiency is still 100%, I lost a couple gigabytes on my scratch disk. Those were only 8-megapixel Canon Rebel files, though. I should try some from my newer 7D.

Julie Sinar said:

as they a 3.5" drives, and I don't like the noise they make, I find it distracting.

Click to expand...

You'll love 2.5" drives then, since they are designed for laptops they tend to be almost silent. It sounds like one of those would make a good scratch disk for you since they are quiet and don't need their own power cable.

Perhaps you are working on some VERY large files with your pano, getting down to 30% seems odd with 8Gig. So, just to double check..... what have you set your RAM preference to in Photoshops's performance tab?

If that didn't make sense, open Photoshop, go to PhotoshopMenu > Preferences > Performance and look at your RAM percentage. You will get LOTS ANS LOTS of opinions on the best setting. Many/most heavy photoshop users are set at 60 to 70%

Also remember that keeping your history states really high costs you performance. You will find that setting in the same place as the RAM.

Hope that helps. If not, the OtherWorld disks suggested earlier in this thread are great!

Julie Sinar said:

Thanks for the information.

I did not think I would need a scratch disk, having 8GB of ram, but while I was putting together a Pano my efficiency went down to 30%, so I think I really need to get one, even just doing regular editing I often drop down to 80% efficiency.

I do back up a lot, I back up to 3 separate hard drives, and keep one at my parents house, so back ups are not an issue. I don't keep them plugged in all the time though, as they a 3.5" drives, and I don't like the noise they make, I find it distracting.

Click to expand...

--
Tom Ferguson
http://www.ferguson-photo-design.com

Tom Ferguson said:

Perhaps you are working on some VERY large files with your pano, getting down to 30% seems odd with 8Gig.

Click to expand...

I could see it going down to 30% if...

• The images are from one of the recent cameras with a gazillion megapixels in each frame
• There are many images in the panorama
• There are several other apps open already consuming a few GB of RAM

I would partition your iMac drive to create a 10GB partition for your scratch disk. An external drive, is not going to be useful as a scratch disk with the bottleneck of either a FireWire or USB connection. Better to put your money into maxing out the RAM of the computer and operating in 64-bit mode so PS can use all the available RAM.

Reason for a separate partition is to minimize fragmentation of your primary partition where you operating system and applications reside. Even better to have a 3rd partition for data and image files as processing of these files by Photoshop fragments hard drives to an amazing degree. Fragmented hard drives can decrease performance by 75% or more when batch processing images.

Keep it local!

G

calson said:

I would partition your iMac drive to create a 10GB partition for your scratch disk. An external drive, is not going to be useful as a scratch disk with the bottleneck of either a FireWire or USB connection.

Click to expand...

Are there numbers anywhere that compare using an external FireWire 800 scratch disk speed versus partitioning a single internal drive? I have always read that if you only have one drive, partitioning it for scratch disk use is not going to get you much because now you're now adding scratch i/o demands on top of the data access requests of the system and Photoshop, and there's only one hard drive mechanism to serve all three competing demands. Now I'm curious as to whether you feel that a current drive can serve all those masters faster than splitting the tasks between the internal drive and an external scratch disk (two independent mechanisms).

I could see where making a scratch partition might be better than not making one if you weren't going to attach any external drives. But I'm still not sure making one disk do all the work is faster than using two disks in parallel over FireWire 800.

calson said:

Better to put your money into maxing out the RAM of the computer and operating in 64-bit mode so PS can use all the available RAM.

Click to expand...

Hopefully they have one of the iMacs that can go to 16GB, since they're already at 8GB.

If you have a current Intel Mac with more than 4GB of RAM in it, the default is that Photoshop will operate in 64-bit mode. Out of the box, no additional adjustment is needed here. Unless you mean turning it on in the kernel...which is unnecessary for this purpose. All the RAM will be seen either way.

calson said:

I would partition your iMac drive to create a 10GB partition for your scratch disk. An external drive, is not going to be useful as a scratch disk with the bottleneck of either a FireWire or USB connection. Better to put your money into maxing out the RAM of the computer and operating in 64-bit mode so PS can use all the available RAM.

Reason for a separate partition is to minimize fragmentation of your primary partition where you operating system and applications reside. Even better to have a 3rd partition for data and image files as processing of these files by Photoshop fragments hard drives to an amazing degree. Fragmented hard drives can decrease performance by 75% or more when batch processing images.

Click to expand...

Very bad advice. Partitioning is almost always a bad idea and offers no benefit as far as Photoshop performance, nor is there any advantage to splitting up the system and data (and impossible to actually do since not all user data is in the home folder). It's also a pain to manage, especially with three partitions, let alone two.

Unless you are doing something like high end video, fragmentation is rarely an issue on Macs, partly because OS X defragments on the fly. Lastly, unless the Mac has over 4 gig of memory, 32 bit Photoshop can accesss all the memory too, and if it has more than that, the scratch files are cached by the system so it's almost as good.

Tom Ferguson said:

Perhaps you are working on some VERY large files with your pano, getting down to 30% seems odd with 8Gig. So, just to double check..... what have you set your RAM preference to in Photoshops's performance tab?

If that didn't make sense, open Photoshop, go to PhotoshopMenu > Preferences > Performance and look at your RAM percentage. You will get LOTS ANS LOTS of opinions on the best setting. Many/most heavy photoshop users are set at 60 to 70%

Also remember that keeping your history states really high costs you performance. You will find that setting in the same place as the RAM.

Hope that helps. If not, the OtherWorld disks suggested earlier in this thread are great!

Click to expand...

Hi,

I have just checked the RAM percentage as you suggested, it is set to 5627mb 72%

The files were not overly large, from a Panasonic G2, there were 10 of them, they are about 5mb each.

I have 30 history states, cache level 4, Cache tile size 128K

Julie

graybalanced said:

I could see it going down to 30% if...

• The images are from one of the recent cameras with a gazillion megapixels in each frame
• There are many images in the panorama
• There are several other apps open already consuming a few GB of RAM

Click to expand...

Hi,

I have just redone the pano again, I made sure I closed all other apps down before i ran it, and my efficiency only went down to 93%, I can't remember what apps I had open last time I did it, I'll make sure I close all unnecessary apps down when I do heavy PS work in the future.
--
Julie

It sounds like you've solved your problem by closing other apps. Nice.

30 history states might be a bit much when working on a 10 image pano, if you find your efficiency going down below 90%, just drop that setting down to 10 until you are finished.

I believe 90% is the Adobe recommended minimum before a faster/separate scratch drive will make a noticeable improvement.
--
Tom Ferguson
http://www.ferguson-photo-design.com