Photoshop RAM, hard drive, resource usage (for geeks who can stomach it...)

I am looking to build myself a really fast Mac desktop computer for Photoshop and Lightroom. I'm a

Mac user with Mac software, so that decision is already made. Right now my only machine is a

PowerBook G4 with a gig of ram. It can really bog down in Bridge and running intense processes on

large files in Photoshop. So, obviously, the main objective is speed. The Mac Pro--the machine I'm

building--has two dual-core Intel Xeon processors. I'm looking for the most bang for my buck, so to

speak. This prompts me to ask a few specific questions.

 

1. Does a multi-processor computer benefit from multiple hard drives? One Mac salesperson said yes,

another said no. One 2003 post here said scratch disc usage can be much faster with the scratch usage

on a separate drive from the OS. Whats the reality today?

 

2. Both Mac salesdudes told me that I wouldn't know what to do with 4 gigs of RAM. They say 2 is all

anyone needs. This conflicts with what I've heard before, and with some of what I've read here in these

forums. So again, whats the reality? 4 gigs would cost me $800 more (!) than 2 gigs. I know that

nothing will slow down a computer like not having enough RAM. So... what is "enough"? Oh... and

does anyone know how multiple processors share RAM?

 

3. What do you think is better--one really big monitor, or two smaller ones? (Or maybe one large one

and a smaller one for palettes?)

 

4. How much difference does the video card make? The Mac Pro on demo at the store, running

Aperture with a large file (maybe 6000 x 4000) was not as fast as I'd have expected. I didn't expect to

see so much spinning beachball on a machine like that. The Macdude explained that computer was

running on the basic graphics card--an NVIDIA GeForce 7300 GT 256MB (single-link DVI/dual-link

DVI). Whatever that means. He assured me that a $250 upgrade to the ATI Radeon X1900 XT 512MB (2

x dual-link DVI) would make it much faster, since Aperture is written to run first on video RAM. But

what about Photoshop?

 

Thanks alot for any advice or feedback.

 

Peter

 

p.s. I know that CS2 is going to run on a G5 emulator with these Intel chips until CS3 comes out. I'm

okay with that.

The ticket is to have enough RAM to give 1.2gb to Photoshop, PLUS at least two fast drives on the bus (that means not USB or Firewire drives.)

 

More RAM is good because you can give 1.2 to Photoshop, and still have plenty left over for the OS and the dozen other processes running in the background. So 4gb is cool.

 

Now, Adobe has a whole page on their site that says the above, and more (especially more for people on the 'correct' Windows platform running XP Server - it can use more RAM.) Check out their site for that info.

 

Screens? One big one, another smaller for palettes. Big is good. Apple's monitors are just fine.

For large file or multiple-large-file-at-once performance enhancement, consider RAID drives. Find out which type will give the best speed boost. I use RAID 0 and it's WICKED fast! In my business, I open 50, fifteen MB tif files at once, to 2 GB RAM. No bogging, very little waiting. With 1 standard drive, this would be a bottleneck.

 

Especially when physical RAM is overwhelmed, having the RAID 0 makes virtual memory faster.

 

Files are split across two drives so they are delivered to memory quicker. Some might consider this a risk because 2 drives may be more prone to failure than 1. There is a RAID configuration which slolves this risk...could be RAID 5 but I'm not sure.

How much ram you need depend salot ont he size of the files your opening, and how many you are opening at once. If it is a 12mb JPEG and your only opening 2 or 3 then 1Gb is fine, if it is 300Mb TIF's and your opening 5 or 6, 2Gb is a must have, 4Gb would be nice.

 

Video car dis not as big a concern unless you are playing games, or rendering/encoding video. As far as Photoshop is concerned a nice 256Mb ATI or Nvidea card will work just fine. You don't need a $500 SLI video card for Photoshop.

 

Now for some tech talk. I'm going to cover the 3 basic and most common RAID levels.

 

RAID 0 is a non parity stripe. It requires atleast two drives and the data is written across both dirves as if they are one, so you can have 2 400Gb drives and it appears to the OS as an 800Gb drive but there is no back up so if one drives fail they both fail and your data is lost.

 

RAID 1 is mirrored. Requires two identical drives and the data is written to both drives and read from both drives simultaniously. The plus is that if one drive fails the other drive is still good and you have lost no data. The down is that if you have 2 400Gb drives you still only have 400Gb usable to the OS. RAID 1 is the best scenario as far as drive speed is concerned. Since the data can be written and read from 2 drives at once the read times are much quicker than with RAID 0 or RAID 5.

 

RAID 5 is a parity stripe. You have to have atleast 3 drives of the same size and data is written acorss all the drives as in a RAID 0 stripe, the difference being is that a 3rd of each drive is used for a backup of the previous drive. Dirve 2 contains a backup of drive 1, drive 3 contains a backup of drive 2, and drive one contains a backup of drive 3. The down side is that you lose a 3rd of each drive for the backup so if you have 3 400Gb drives you still only have 800Gb usable to the OS, but unlike RAID 0 if one drive fails the other two drives will contain all the information of the failed drive and you lose no data. Since the data is written and read across multiple drives this configuration is not as fast as RAID 1.

 

Honestly I wouldn't worry about RAID. As long as you get a 7200 or 10K RPM drive you'll probably be fast enough. And if you get two drives you can just have two seperate drives, RAID is just an added headache, especially RAID 0 if you ever have a drive fail.

 

Cheers.

<p><i>"1. Does a multi-processor computer benefit from multiple hard drives? One Mac salesperson said yes, another said no. One 2003 post here said scratch disc usage can be much faster with the scratch usage on a separate drive from the OS. Whats the reality today?"</i></p>

 

<p>The number of CPUs doesn't determine whether it benefits from multiple hard drives. The general recommendation is to put your OS on one drive, swap file on another drive, and scratch disk on another drive. RAID can increase bandwidth, but not necessarily latency (unless you've got an awfully good RAID implementation, which you likely don't), and not at all with contention. Splitting those tasks across spindles makes good sense.</p>

 

<p>In addition, if you specify multiple scratch disks in Photoshop, it will try to balance among them in a manner that makes sense for the way in which it uses the disks. Windows swap shouldn't be used for anything significant under normal usage (or you need more RAM!), so I don't worry about it.</p>

 

<p><i>"2. Both Mac salesdudes told me that I wouldn't know what to do with 4 gigs of RAM."</i></p>

 

<p><b>You</b> might not, but between your OS's disk cache and Photoshop's unsatiable apetite for memory, your <b>computer</b> will know what to do with it.</p>

 

<p>That being said, the difference between using Photoshop on 2 gigs and on 4 gigs only becomes noticeable when you have either very large files open, or a good number of files open. I have a number of machines at my disposal, and only occasionally do I need to go to the one with 4 gigs.</p>

 

 

<p><i>"4. How much difference does the video card make?"</i></p>

 

<p>Next to none, unless you're talking about playing 3D games.</p>

 

<p>As for multiple processers, you don't need to go crazy. Between my single, dual, and quad-core systems, the time it takes me to work on photos isn't really greatly reduced. I spend far more time making selections, creating masks, deciding on crops, etc. than the the machine spends processing. A single dual-core chip is very sufficient.</p>

In terms of memory, stick with 2GB for now. FB-DIMMs are very new technology and

massively expensive right now. Try the 2GB configuration for a few weeks and see if it really

is limiting you in any way...coming from a PB G4 with 1GB of RAM, the immediate speed

difference is going to be huge relief anyhow. If you find you need that extra 2GB of RAM right

away, you can just add it in, but if you hold off for several months you'll likely save some

money as those FB-DIMMs come down in price.

You're buying a 64-bit machine, the <i>whole point</i> of which is that it can use much

more memory than 4Gb, without involving the disk at all. All the shenanigans with fast

multiple disks needed on the current 32-bit machines will disappear. You will stuff the

machine with (I'm guessing) 16Gb of memory and never see a swap-busy beach ball again.

<p>

The catch is that the software to make the 64-bit hardware sing like that hasn't been

finished yet. Not the OS (Leopard, now in testing and due out next year I think), and as far

as the public knows not Photoshop. And memory is currently dear.

<p>

On a 32-bit machine, each process can only use 2 ** 31 [2 to the power of 31] bytes, or

2Gb, no matter if 4Gb is in the machine. This is not enough to efficiently process large

photographic images. But 2 ** 63, as on Leopard with the Mac Pro, is. It is actually many

millions times more memory than you could put in that machine - now the question

becomes "How much can I plug into the motherboard?"

<p>

So, what you get now is temporay, waiting for new software and cheaper memory. You will

be buying more memory later (looks like 6 or 7 more 2Gb DIMMs). Previous posters are

correct that Photoshop won't use more than 2Gb and more than that is useful only for

caching disk.

<p>

Now, the "geeky" answer you wanted about multiple CPUS. Each "program" (technically,

"process") can have any number of "threads", each of which does processing on the

program's memory. If there are two threads on a 2 CPU machine, and nothing else is

running, the processing will happen at once. All of the threads share the same memory

(the hardware makes sure the exact same memory word is not accessed at once). They do

not each get their own 2Gb address space, because they are the same process. But an

image processing program can be written so that one CPU is working on one part of the

photograph while the other is working on another, <i>as long</i> as both parts are in

memory. If the disk is working, some part of the picture isn't in memory yet but needs to

be. You could write the image processing program to think ahead about what it will soon

need, but it's much more complex than just having it in actual memory. Whether Adobe

did this, or even whether they split the image into two for two CPUs, I don't know.

<p>

Would 4 CPUs help? Unless Apple have rocks in their head, any 64-bit version of Aperture

will be able to split a large photo up into <i>n</i> parts and work on them

simultaneously, where <i>n</i> is the largest number of CPUs in a machine Apple sells.

Adobe will have to follow with Photoshop, if they can (it's harder because it's an old

program). If they can't, their product will be slower and those wedded to it will be wasting

the extra CPUs.

Photoshop won't use more than 2Gb -> the current Photoshop won't...

<<1. Does a multi-processor computer benefit from multiple hard drives?>>

 

Multiple hard drives would have no effect on Multi-processors what-so-ever. Your machine WILL benefit from having a faster scratch disk set to other than the drive your application is on however. My experience has been to use a fast, empty (nothing ever written to it other than scratch files) RAID 0 array. If you REALLY want to get geeky, partitioning the drives and using the outer most partitions are even faster. Imagine being on a merry-go-round and standing in the center versus standing at the edge. The outer edge is traveling at a much faster velocity.

 

<<2. Both Mac salesdudes told me that I wouldn't know what to do with 4 gigs of RAM. They say 2 is all anyone needs.>>

 

Under 10.4.x Photoshop uses 3 gig of RAM maximum. See Adobeﾒs tech support page. http://www.adobe.com/support/techdocs/320005.html

However CS3 that limit will be raised substantially (Sorry Nondisclosure Agreement comes into play here.)

 

<<3. What do you think is better--one really big monitor, or two smaller ones? (Or maybe one large one and a smaller one for palettes?)>>

 

I have used three monitors for years, no matter where you put your palettes, they are ALWAYS in the way. Using the Tab key to hide them is NOT a substitute. ;-) I have one for the main image, one for palettes and one for a ﾓpreviewﾔ window where I have a second window of the image opened and view at full screen. You would be amazed how much time this saves not having to zoom in and out to see detail. the best part is that you donﾒt need really high quality monitors for palettes and preview.

 

<<4. How much difference does the video card make?>>

 

If you working on very large files a faster video card can make a big difference on screen redraw and scrolling but if your files are smaller, ie:10mb I rather doubt you will see any difference. Further, I would not waste money on a fast video card to run you secondary monitors.

 

<<p.s. I know that CS2 is going to run on a G5 emulator with these Intel chips until CS3 comes out. I'm okay with that.>>

 

Given that CS3 is at best 6 months out, running in emulation will give you a performance hit but even in emulation it will be ﾓserviceableﾔ. Photoshop has not been totally recompiled since Version 3 and with Both Both Windows and Macs using Intel based processors optimizing is showing some very nice performance gains (again NDA comes in to play but it is substantially faster)

 

Regards,

 

Will

 

Adobe CTI Photoshop

Thanks to all of you... this has been very informative.

One last thing:

regarding RAID... say I put two identical drives in my computer, and want to run them as a

RAID 1 configuration. How do I let the computer know?

Never mind! Did some more surfing, starting with all this good information. I believe I'll

build it with 2 500 GB drives in a RAID 0 array, plus a third drive--a much smaller one,

whatever I can find that will fit--to be a dedicated Photoshop scratch disk. I already have a

300 GB firewire 800 external drive for backups. Thanks again to all of you!

You won't regret RAID. It's a big performance booster, all around.

 

I brought a data DVD to the Apple store and and asked them to copy files to HD, then open a dozen 64MF tif files, all at once. It was their fastest G5 with tons of RAM.

 

tick...tock...tick...tock...zzz

 

Single 7400 rpm drives don't open files the way RAID 0 does. No comparison!

 

I eventually went with a Dell system, preconfigured with RAID 0, and I might add...$2000 less than the G5 with no RAID. I have 1/2 terabyte of storage (two 250 GB drives)

RAID 0 is a waste of time. Theoreticaly it should work but in every practical test that I have carried out even with 10krpm raptors it has little speed advantage over a single dedicated scratch disk. More than 2gb of RAM is repeat IS usable by CS2 on both XP64 and the latest Mac OS.

In regards to the debate over how much RAM Photoshop CS2 can *actually* use I urge anybody interested to take a look at this link:<P>

 

http://photoshopnews.com/2005/04/04/photoshop-cs2-how-much-ram-fact/<P><I>The the machine I'm building--has two dual-core Intel Xeon processors</i><P>If you are indeed "building" as you say, then you should have the option of using a single 3ghz 2 Core duo vs two 2.66ghz Xeons. The former would be faster for most apps and much cheaper, but unfortunatley you don't have that option.

<I>I brought a data DVD to the Apple store and and asked them to copy files to HD, then open a dozen 64MF tif files, all at once. It was their fastest G5 with tons of RAM.</i><P>That's a poor way to judge a system's performance because it has little to do with write speed of the drives and far more to do with how you choose to do the copy from the DVD and the way it's cache'd. For instance, on that Dell you bought running Windows I could drastically alter how long it took the copy that DVD by simply choosing RAW vs a Core mode (GUI based copy).<P>Unless you're doing uncompressed Hi-Def capture to disk in real-time, my vote is to avoid RAID 0.

Scott misunderstood me. Opening the files, which had already been copied to the hard drive, was what took so long.

 

My RAID drives read and write files seemingly twice as fast as a single 7400 RPM drive.

 

With my business, which is scanning slides, opening lots of large tif files at once is a common occurance. I edit most of them, and close each as I go.

 

RAID 0 has saved me LOTS of time with both read and write...no question about it. I'm not saying ZERO is the best way, only that is WAY faster than a single drive.