Photoshop CS Memory Doesn't Match To Installed

Hi!
I have tried to find an answer to this strange question. I am working on dual 2GHz G5. Recently I added extra Kingston memory chips and the total was 2.5GB. But I noticed the Photoshop CS Memory prefs shows 1810MB available only. Today I added another 1GB, so the total installed RAM I have now is 3.5GB, however Photoshop still shows the same amount. Then I removed 2.5GB RAM and left 1GB on the machine and I was surprised. I got the following results from different RAM configurations:
•With 1GB RAM installed Photoshop shows 911MB available •With 2GB RAM installed Photoshop shows 1862MB available •With 3GB RAM installed Photoshop shows 1811MB available •With 3.5GB RAM installed Photoshop shows 1804MB available It seams the application shows the correct amount when it is below 2GB. That's all I can think of now. Please help me to solve this problem, anyone!
Yegor H.

That is correct, but not a problem.

The OS limits applications to 2 Gig each.

And no matter how much is installed, Photoshop can't use all of it - the binaries and OS take up some space.

Thanks Chris for the information!
Does it mean that I won't gain more performance with the extra memory I added? Yegor

Yegor,

Chris has explained this many times here. If you do a search on this forum you'll find that this has been discussed here very often.

Read the following recent thread starting with post # 5, for instance:

g ballard "Photoshop CS + Panther crashes" 4/27/04 3:26pm </cgi-bin/webx?14/5>

as well as this other one, coincidentally also from post # 5:

<http://www.adobeforums.com/cgi-bin/webx?7@@.3bb3cccf/0>

In OS X the old RAM allocation does not exist any more. The % you define is the maximum percentage of available RAM Photoshop is allowed to grab for itself at any given time. Because OS X allocates RAM dynamically, available memory changes constantly.

Because any application can use no more than 2GB of RAM anyway, if you have 4GB of RAM (or more) you could give it 100%. I'd still go with 90% or 90% anyway, since the theoritecal 2GB limit is really a little bit less than 2GB.

Don't give Photoshop 100% -- 80% is safer.

With 2 Gig or more, address space fragmentation eats further into the available space -- and in CS we didn't allow enough "slop" to account for it all the time.

Yegor,

What you gain with more RAM is the ability to run other applications simultaneously while Photoshop uses the maximum amount of dynamically changing memory it can.

Thank you very much guys.
Your answers really helped me. I was confused and thought something wrong was with the system. I have one more question. Which is the best: leaving cache on 4 or making it 8, and what's the difference? Does the cache level affect the performance?
Thank you in advance!

As per

<http://www.adobeforums.com/cgi-bin/webx?13@@.2ccfe4c0/7>

Also, make sure the cache level (pyramid) is set to 4 in preferences.

Chris hasn’t gone into details, but I'll take his word for it. :)

Chris Cox - 10:47pm May 7, 2004 Pacific (#4 of 7) Don't give Photoshop

100%

This is different advice than what's been discussed in the past???

Now I'm confused...

Gary,

It is different than some of what has been mentioned here before, but in all fairness to Chris and other participants it needs to be pointed out that the 100% figure was not touted as advice, but rather it originally came up in the context of someone asking insistently if it was OK to give Photoshop 100% of RAM if you have 4GB or more installed. The advice has always been to set it between 65% and 90% depending on the amount of RAM you have. If you have very little RAM, even less might be advisable.

And yes, I agree with you, this topic is indeed very confusing. Among other things, it needs to be addressed in a more extensive article by the gurus. It's understandable that Chris is very busy and his replies are just a few lines addressing a very specific question.

Ian recommended some time ago to set memory at 100% with 4gb installed. That got me thinking about it.

You and I just slugged it out in another thread.
g ballard "Photoshop CS + Panther crashes" 4/28/04 11:05am </cgi-bin/webx?13/9>

Sorry, I am still confused.

The rocket science may well be confusing, but confusing users who are trying to set a simple memory setting (that doesn't make comon sense) is convolution, IMHO.

Gary,

Here's an excerpt from the thread to which your link (same as mine) points:

[Post#12] If you have 2.5GB of RAM and set Photoshop to 100%, it will take up to 100% of whatever RAM is available, not necessarily 100% of the nominal 2GB limit it can use (Chris explained that limit is really appx 1.9GB or something like that because of some overhead). It can be less but not more than that appx. 1.9GB limit.

What is new, definitely, is the latest post by Chris Cox in this thread:

Don't give Photoshop 100% -- 80% is safer.

With 2 Gig or more, address space fragmentation eats further into the available space -- and in CS we didn't allow enough "slop" to account for it all the time.

This comment doesn't necessarily contradict anything he has said before, but it does bring a certain ambiguity to the equation by virtue of the inclusion of space fragmentation. It's not clear whether setting Photoshop RAM to 80% actually reduces space fragmentation or just the need to use already fragmented space.

G,

I don't recall making such a recommendation, but I have quoted advice from Russell Williams in a few threads.

See this version from the Windows forum (it's in here as well somewhere)

Ian Lyons "PS 8 Photomerge and RAM" 1/3/04 10:25am </cgi-bin/webx?13/14>

It "may" seem like Adobe can't make their mind up on this either, but that seems to be more down to what 100% actually means within the Prefs dialog. Some things that might help you better understand:

1. Photoshop can't use more memory than allocated.

2. Photoshop makes a poor guess at FREE memory based on the installed amount up to 2GB (hence Yegors table). By poor I mean it thinks it has more than it really has. Not by much but it can be enough fair you to get into trouble.

3. If you set 100% then Photoshop can use ALL of the amount guessed at in 2 above.

4. Photoshop can't work beyond the 2GB limit. So setting 100% means that less than 200MB is available for those Photoshop features that operate outside the prefs allocation (some plugins and filters - includes those from Adobe but can't recall which).

The bottom line is that with more than 2GB of ram you can set 100% and you'll therefore give Photoshop around 1850MB to work with. However, be careful that the plugins and filters mentioned in 4 above don't come into play. Given the number of differing opinions coming forth I would (only on boxes with more than 2GB) tend to air on the safe side and set the Photoshop allocation to no more than 95%. No doubt there will be differing opinions, but that doesn't mean they're any more/less correct then me/you or my neighbors pet labrador. I think the following is a more reasoned way of determining the best setting:

Originally Posted by Scott Byer on Windows forum

Tuning Photoshop CS:

Open Activity Monitor. Go to the System Memory tab. The number to watch is "FREE". Better still use X Resource Graph ( <http://www.starcoder.com/xrg/> ) and read Availbe in lieu of Free.

[Originally Posted by Scott Byer]

Start Photoshop and start working. That FREE number will decrease and, after a while, will often stabilize out.

Is it below 15000 (15MB)? Your Photoshop memory percentage is set too high. Lower it and try again.
Is it above 50000 (50MB)? If you really have been doing things you normally do, including running a filter and you still have more than 50MB free, you're probably leaving a little performance on the table (but not as much as you think!). Consider increasing Photoshop's memory percentage slightly.

If you *really* want to get technical about it, bring up Performance Monitor and set it up to track a few things (free memory, disk activity, memory paging rates).

What you are trying to avoid is having the OS page out Photoshop's memory. We don't lock down Photoshop's memory because that causes many, many more problems than it solves. But when Photoshop has allocated a lot of memory, some of it looks to the OS as "not busy" and will get paged out if RAM gets low. If Photoshop's scratch and the OS paging file are on the same physical disk, this is doubly bad.

Ian,

2. Photoshop makes a poor guess at FREE memory based on the installed amount up to 2GB (hence Yegors table). By poor I mean it thinks it has more than it really has. Not by much but it can be enough fair you to get into trouble. >
3. If you set 100% then Photoshop can use ALL of the amount guessed at in 2 above.

Thanks for the input. That “poor guess” bit is indeed enlightening and might explain the reason for some of the ambiguity in this topic.

On the other hand, if Photoshop thinks it has more available RAM than it really has, Yegor's table can only be explained by assuming that other stuff was using up memory resources when he noted how much he had available with the largest amount of RAM at his disposal.

Thanks, Ramón.

I have a very simple brain and rely on logic and common sense to grasp this stuff.

By CC's "80%" statement, it appears I am wrong and confused.

Ramon,

Keep in mind how I defined "Poor" - I don't want folk thinking that I suggested sloppy programming.

As for CC's explanation of Yegors table, it's the first time I've come across this and it appears that CC is holding his hands up to sloppy programming (I'm kidding). Even so it could be that I'm off his Xmas card list, again ;-)

Ian,

Your disclaimer is hereby properly acknowledged and understood. :)

If I really wanted to drive myself nuts, I could start investigating how RAM gets allocated to Classic itself and to any Classic application (e. g. LivePicture) when Photoshop CS is already running.

Forget I said that. I'd better not even think about it. %D

I thought there were supposedly "hacks" (according to a friend of mine) in the underlying OS X memory management system that allowed a mostly 32-bit OS to access a 64-bit amount of memory? Or no?

Hmm, maybe it's the fact that you (Adobe) guys are still CFM-based (rather than Mach-O) that's the limiting factor? (Well most of you, I should say. Distiller 6 is an interesting start. :-P )

If that's indeed the case then I think the statement "The OS limits applications to 2 Gig each." is a bit misleading.

After all, how is the OS itself able to access more than 2 GB of RAM?

No, CFM and Mach-0 have the same limitations.

The OS kernel can access more because it isn't an application.

Hey screw OSX make PS 8-9-10 and so on run in os 9. Best OS EVER. At least I can type in what I want, not slop and guess.

....Asa

Thanks Chris..

Yeah, after thinking about it, I wondered if the "hack" was at that low of a level, and not "available" in a sense, to other higher level applications...

So, say you had 6 GB of RAM. If you made a 3 GB RAM disk, which you chose as your only "scratch" volume in Photoshop's prefs, would that be a way of utilizing more than 2 GB of RAM?

Sort of.

But the OS would normally use unused memory for disk caching anyway....

Asa, you really show your ignorance with comments like that. If that's all you have to say it would be better that you say nothing.

show your ignorance<<

Thanks Buko there has been many times I thought some comments you made fit that same line. To bad I thought you were above name calling.

I thought this was a free country in which to express my opinions. You just expressed yours. Just because I like OS9 does in no way infringe upon your use or love of OSX. I just do not recall Adobe dropping support for a entire OS, the ones that are still in use anyway (windows). It appears Adobe has dropped a few programs for the Mac totally so...

That's all. Have a happy life.

....Asa

Asa I'm not name calling just stating a fact. You did say:

Hey screw OSX make PS 8-9-10 and so on run in os 9. Best OS EVER. At least I can type in what I want, not slop and guess.

Adobe didn't stop supporting OS9, Apple did. If Apple is not supporting it why should Adobe? Are you willing to pay the hundreds of thousands of dollars so Adobe can program the app twice? for a dwindling OS9 user base.

OS9 Best OS EVER.

This is the part that you loose your credibility. If you call Crashing everytime you push the system to its limits the best you are welcome to it.

This is the part that you loose your credibility.<<

Buko I never had many crashes putting it to OS9.x. Perhaps luck perhaps knowing how to use my system. I do use PSCS and Quark 6.1 running OS 10.3.3 with few issues. Now having said that you have to wonder about upgrades for OSX. You never know with a Apple upgrade if you will have a running system or not. With X it can be a long road to recover full use. OS 9 takes 1/2 hour or so if a download or perf craps out. Tiger is due out soon, what other surprises are we to face, who knows. I don't need to discuss this with you any more. We tend to agree to disagree.

Happy day
....Asa

never had many crashes putting it to OS9.x.

Me neither but I had them. If I left my machine on all night it was usually locked up in the morning. This just does not happen with OSX. Sorry you are having so much trouble with OSX, it must be because you are using Quark 6.

Buko,

My old Frankenmac would go on for weeks without being turned off on 9.2.2. I'm adapting to Panther 10.3.3 gradually, but I still think 9.2.2 was a far better release than any flavor of Cheetah and Jaguar.

it must be because you are using Quark 6. <<

Nah Buko, I have not crashed Quark 6.1 yet. PS8 has been ok, but a real slug with some type and large images. Tiger is due out soon...can't wait for the next round of fixes. But I'll wait till you install it first and watch your progress. <grin> Man I removed ID3 and my system perked right up, must have been the extra bloat. Say I purchased a couple firewire drives with the money I saved by not upgrading Acrobat, good deal huh?

Cheers...

....Asa