I’m just setting up a new edition dual 2Ghz G5 purely for photoshop use. It has 4Gb ram, 2 x 260GB drives and the GeForce FX 5200 video card (64mb) driving a 23" Cinema display.
I am wondering on the optimum set up for PS ? I have read that PS can only recognise and use up to 2 Gb ram – is this true, and if so is this likely to be fixed with an adobe update, or will it be in PS "9" ?
I have partitioned 20gb of HDD space on the second Hard Drive and assigned this as Scratch disc space. The OS (10.3.4) is on the first HDD. Is this the best way ?
Finally, would an upgrade to the ATi Radeon 9800 Pro Mac SE card, with 256mb vram, give me a noticable increase in screen redraw speeds ? All the reviews talk about its capabilities purely in terms of gaming !
The 2GB limit is universal in all 32-bit operating systems, not just OS X, and it has absolutely nothing to do with Photoshop. Do the math.
Until true 64-bit operating systems, like Apple’s Tiger or Microsoft’s Longhorn are released. nothing can be done about this. They are at least a couple of years away, by which time there will be even more state-of-the-art Macs, alas.
In short, your G5 is 64-bit capable, but OS X is not.
You can use your extra RAM to run other applications simultaneously. Others have suggested a using part of the RAM to create a RAM disk to use as scratch disk, which could give you an extra speed boost.
This has been discussed here often. Do a forum search on key words like 32-bit 2GB Chris Cox.
I’ll have a further search around for stuff – the ram disk idea is a nice one – I’ll give it a go.
I noticed you mention an 80GB scratch elsewhere – I was always led to believe Scratch should be based on four times max file size (in my case around 3Gb). Is there a formula for Scratch size, or is it just bigger is better ?
As far as Photoshop screen redraws are concerned, changing your video card is unlikely to have any noticeable effect. Graphics cards are defined more by their 3D performance these days. Video RAM is used mainly for complicated and highly detailed 3D scenes, such as those found in games and high-end 3D modelling applications.
Thanks for your reply Graham – i’ll stick with the present video card and see how it goes.
One more question for everyone. As I have two 160Gb Serial ATA drives in the G5, I can set the Mac up to treat them as a single RAID system – but this would not allow me to split a partition to create a Scratch Disc. Should I stick with separate SATA drives with a Scratch partition (around 20Gb) on the second HDD ?
You’ll have to wait for someone else to reply regarding RAID tips as I have no experience with this. But your present system (OS on one physical drive, scratch disk on another) is the right way to do it if you aren’t using RAID. Or, you could use an external FireWire drive for the scratch disk which would be just as valid.
I was always led to believe Scratch should be based on four times max file size (in my case around 3Gb).
Those are some BIG files you’re working with, Tony! π
As far as scratch disk drive space, all kinds of figures get bandied about. It depends not only on file size but also on other factors like the number of history states you have set in your preferences.
My biggest files are scans of medium format negatives, and I have my scratch disk set to a 50GB dedicated partition on an otherwise unused, separate drive. I could actually increase it if necessary because I have a lot of free space available on four internal drives and two external FireWire drives, but it’s been enough so far.
Four times file size does sound tight. The smallest amount I’ve seen recommended is ten times the largest file size, and 30 times is commonly suggested. The 80GB figure was the largest I had read about at the time.
Look at the Efficiency percentage as you work on your files. If you’re consistently at 100%, you’re fine.
So taking the above Adobe article into consideration, they are saying that Photoshop – in effect – CANNOT acquire 2GB of RAM from the system at a time, but only 1.7GB (roughly). This is misleading IMO since it’s often noted by Adobe that it is possible for Photoshop to utilize 2GB worth…
….at the place I work we just installed 3.5 GB on one of our machines running Panther, and if I max the percentage out, it still only achieves just over 1.7 GB with nothing else running, immediately after system boot. This would be fine if this is what was advertised / listed under the support literature, but it’s not. I never personally had any issues with this because my machine has only 2GB and so I never had an opportunity to see what happens on a machine with 3GB+.
Is there any way (using UNIX or some GUI-based tool) to tell the system to free up x amount of RAM for an app, or to limit the amount of RAM the system can store away while its idle? If you install 4 GB as the article seems to imply (but not spell out), will there suddenly be 2GB worth of RAM available? My boss is not going to be pleased if I have to tell him to shell out yet another $200 for another two sticks of Crucial (since the OEM stuff is still in there at only 256MB each)….
Yes but that only makes sense if you have roughly 2GB installed and no more. It makes no sense if you have well over 1GB available to the system, even after the first 2GB is – in theory – allocated to Photoshop (or any other app). I have done a forum search (after I had already found above-noted tech article)… that’s how I wound up here instead of posting a new thread.
Well OK… but uh… intuitively speaking why would you expect someone to search "Chris Cox overhead" instead of say "RAM allocation" or "Photoshop CS RAM", etc?
See, for example, post # 5 in ths thread; Chris Cox "PS should make use of all available memory but doesn’t!" 4/21/04 4:12pm </cgi-bin/webx?13/2>
Β because of OS overhead and address space fragmentation. Basically, there’s a lot more of it than we accounted for when writing CS.
And it also wasn’t a good idea to set the slider to 100% in previous versions.
Camera RAW, and other plugins, run in Photoshop’s memory space. Thus they share the 2 Gig with Photoshop. Sometimes, if Photoshop is running out of memory, the plugin will also run out — even when the OS says memory is available (especially thanks to fragmentation).
Ah. If only I knew the correct search term before making an attempt! π
All right let me ask another way: is it possible that with 3.5 GB (or 3584 MB roughly) installed and an allocation percentage of 60% (which is slightly more than 2048 MB), that the number Photoshop *shows* as being available (something close to 1780 MB) is actually *less* than what is available behind the scenes?
IOW, let’s say I open a file and perform some task that in theory would require 1900 MB of physical RAM (based on the file size, etc.). Using the above conditions, with nothing else running but the system… would 1900 MB be "released" by the system for Photoshop to use (since that number is less than the maximum under the 60% allocation, and certainly less than what is physically available), or does it just get stuck at 1780MB and uses VM for the rest?
It’s not the System withholding memory from Photoshop. The 1.7GB is the maximum that any application can use for now, until a 64-bit OS is released.
And, of course I wasn’t saying you’re expected to know those key words. That’s why I pointed them out to you, because I had read those messages earlier.
Your answer is both disconcerting and a relief in a way. Basically, this means adding another 512MB won’t do squat to increase Photoshop’s share (so no need to recommend the expense). But also a bummer in that it’s a bit of an artificial limitation (imposed by Apple or not).
I won’t even ask if Tiger will make a difference, based on the literature here <http://www.apple.com/macosx/tiger/64bit.html> . Who knows what aspects of the newly planned system will change in the next 12 months….
Anyway, I guess what puzzles me (even being a fairly big propellerhead myself) is why, if the System is able to address any chunk of that 3.5GB, it can’t look at the apps running and see if one of them "wants" the "the first 2GB" based on a preference setting. I mean, what difference does it make to the system which banks of RAM it has to access. RAM is RAM is RAM. Just seems kind of arbitrary… like there’s a litte brat inside everyone’s computer saying "nyahhh! I could give you this extra 200MB, but I’m not going to!"
this means adding another 512MB won’t do squat to increase Photoshop’s share (so no need to recommend the expense).
Exactly right!
I won’t even ask if Tiger will make a difference,
Not in the first few releases. Tiger is "kind of" true 64 bits. Applications will still need to be re-written.
= why, if the System is able to address any chunk of that 3.5GB, it can’t
look at the apps running and see if one of them "wants" the "the first 2GB"
We’re not in Kansas any more. π OS X does not work like 9.x and earlier. Available memory is allocated dynamically, it changes continuously. If you set the slider to 100%, then Photoshop will grab whatever it needs at any given time, up to 100% of the dynamically changing available memory, and no more, but in any case never than the 2GB we talked about earlier because that is the nature of 32-bit application and 32-bit Operating Systems. The reason you see only 1.7 GB is because of the Photoshop-dictated overhead Photoshop requires for its plug-ins to run.
Read carefully this excerpt from the Apple blurb in your link
"TigerΒs new 64-bit features enable developers to address massive amount of virtual memory for command-line applications, server applications and computation engines …
"Not in the first few releases. Tiger is "kind of" true 64 bits. Applications will still need to be re-written."
"TigerΒs new 64-bit features enable developers to address massive amount of virtual memory for command-line applications, server applications and computation engines …"
OK, so you are calling Tiger kind of 64bit because even after rewrites, an application is going to have a restricted amount of useable RAM but unrestricted VM?
I did notice the VM part of Apple’s blurb, and also understand that apps will need to be re-written in general before they can take advantage of the memory offerings of a true 64-bit system… which is why I didn’t bother going into that because I would the farm that Photoshop is not going to be re-written anytime soon.
I guess we’re stuck with 1.7GB for a couple years at least.
So now the question becomes how much more is Tiger really going to offer us? If we can’t max out the use of all the extra RAM on PS (when rewritten) without still depending on VM and there are only 2 drive bays on a G5 to share files, System VM and PS VM how is Tiger going to be 64bit other than claims of being able to address more VM?
Addressing more VM is not what we need. Addressing more physical memory is what we need. I did a little more reading and honestly it doesn’t look like we’re anywhere close (i.e. 10.4 isn’t going to provide the framework to do this most likely, otherwise they’d be happy to brag about it, like they brag about all their other technologies).
Remember the good ole days when a 300MHz computer and 256MB of RAM seemed like a lot? Now we are worried about / struggling to reach 3000 MHz per processor, and 2048MB of RAM per app. All in the span of about 8 years or so. Amazing…
Indeed I do. I remember when our high school yearbook editors salavated at the thought of getting the just-announced Macintosh Quadra in the office (the one Apple advertised with the speeding motorcycle ripping through the desert). Our labs used the paltry ][E so the thought of a real Mac to use for our after school projects was other-worldy.
I was holding off for a new G5 till Tiger came out figuring I would end up with a Mac "tailored" for Tiger. Since Jobs says they have hit a wall with the 90nm technology (maybe 3 ghz by then) and accessing more RAM seems out the window then any G5 will do with an external FireWire drive attached. About the only true 64bit thing regarding Tiger will be Apple’s hype. Gee, maybe when Tiger comes out LaCie will announce a new line of drives – LaCie Big VM π
I have used both the dual 1.8 and dual 2.0 GHz machines on a regular basis and can vouch for their excellent performance. Far better than any dual or single processor G4 I’ve ever used. By next Spring, it’s likely the G5 line will have been bumped again though I suspect it will not be to 3GHz as that’s been very slow going for the industry as you point out.
Probably something like another 200MHz per chip on the high end, and the dual 2 will become the low end. If that happens my recommendation to you would be to buy the middle machine in the lineup. I am sure the dual 2.5 is going to keep you very happy for a long time in terms of processing and data moving power, and it will save you a nice chunk of change to use towards getting yourself more RAM (which I wouldn’t buy from Apple).
Depending on how many apps you will regularly have open at the same time, I’d say anywhere between 2 and 4GB should do well for you. If you will frequently have multiple apps from the creative suite running at the same time, I’d err on the side of 4. Mostly my workflows consist of running either Photoshop CS and FlexColor (hopefully that will end soon with an ACR update – FlexColor is a disaster), or Photoshop CS, GoLive CS and several browsers together. Non-creative workflows are usually a browser, email, Excel, Word and iTunes. None of those scenarios cause the machine to grind to a crawl, although working on multiple 22MP, 16-bit images can certainly slow the pace.
I am probably going to buy another GB soon and leave it at that, since RAM is cheap right now and I could use a little more than what I have to get optimal results in some situations.
Rather than all this speculating about what the present OS can and cannot do, it might be worthwhile reading Apple’s documentation <http://developer.apple.com/>. Good luck, you have to be a saint not to be bored to tears with it.
Walter your arithmetic is correct. I’m not sure what they are using that last bit for. When we used to use 16 bit machines all 16 bits were used for addressing memory.
Hey, folks, it’s not an Adobe thing, an Apple thing, a Microsoft thing, or some conspiracy to keep the oppressed masses down. It’s a fundamental computer science limit. 2^32 = 4GB, the top bit is usually used to help distinguish system address space from application address space, so applications have 2^31=2GB of address space to work with.
Yes, it’s 640k all over again.
The solution? 64-bit chips, OSes, and apps. That’s going to take a few years.
Bold face and colors aside, here’s something from Apple:
Memory Management in Mac OS X
"Unlike earlier versions of Mac OS, Mac OS X includes a fully-integrated virtual memory system that you cannot turn off. It is always on, providing up to 4 gigabytes of addressable space per process. However, few machines have this much dedicated RAM for the entire system, much less for a single process. To compensate for this limitation, the virtual memory system uses hard disk storage to hold data not currently in use. This hard disk storage is sometimes called the ΒswapΒ space because of its use as storage for data being swapping in and out of memory."
Again, what Apple says is different, and very interesting. There was a 2 gig limit — it wasn’t the OS, but the hardware. With the G5, that limit is up substantially.
Take a look at this little chart comparing the machines:
Addressable memory in the G4 is 2 gigs Addressable memory in the G5 is 16 gigs.
So before the G5, an address (user or system) could be only 31 bits — which is not what the post in February said. Now the newer machines are capable of addressing much, much more, and the OS is able to handle 4 gig per process. That’s what Apple says.
I suppose Adobe and other software makers will take advantage of this extra power when and if their customers clamor for it.
Walter, I don’t see where it says that processes in Mac OS X can address 16GB. My understanding is that that document is comparing processors, not OS support.
the OS is able to handle 4 gig per process. That’s what Apple says.
Let’s, for the sake of argument, assume that "what Apple says" is not corporate doublespeak.
How does that in any way contradict what Adobe Photoshop programming guru Scott Byer wrote? As I quoted:
It’s a fundamental computer science limit. 2^32 = 4GB, the top bit is usually used to help distinguish system address space from application address space, so applications have 2^31=2GB of address space to work with.
We’re not going to get beyond these RAM limitations for a long time evidently, so let’s just drop the where-fors and whys. Apple and Adobe both have to make a commitment to overcome these limitations, not just one or the other. And of course, money will always play the biggest role. Even if something is technically practical to do and there is enough time to do it, if a developer doesn’t forecast that they will make added profits from it, they usually balk.
You can bet your bottom dollar that Apple is working on it! (So is Bill Gates on the dark side.) Make no mistake about that. The benefits of 64-bit computing are huge.
It just takes a lot of time, perspiration and money.
I think he means obvious in the sense that Adobe has gotten into the habit of announcing simultaneous releases for Windows and Mac, with respect to Photoshop, InDesign, Illustrator and GoLive (the core suite IOW). So it would make sense that Adobe will go 64-bit with their core apps, when both platforms have the foundations in place to do that effectively. Apple is closer than MS obviously, but even with MS out of the picture it will probably be the release that comes after 10.4 that will bring us the changes we require at teh system level, in order for everything else to fall into place. So, you’re talking two years at least most likely.
Meantime, let’s hope the second edition of the Creative Suite will have some performance improvements in other areas.
No, I meant "obvious" in the sense that Adobe, like all other software developers, must have a pre-release version of the OS before they can develop an application.
Hence the foundation thing I mentioned. π Neither platform has the foundations in place, although OS X seems like it will be about half way there with Tiger.
Graham: My post No. 44 is talking about hardware. I said so: "There was a 2 gig limit — it wasn’t the OS, but the hardware." And: "Take a look at this little chart comparing the machines:"
The link in my post No. 41 is talking about the OS.
What this means is that you could write a program and compile it for a G5 running Panther and have it use close to 4 gigs of ram (since the O.S. does reserve some memory space and there is always some fragmentation).
Is it worth it for Adobe to push for it?
Ramon: I didn’t know who Scott Byer is, and I’m sure he’s a fine person and an excellent programmer, but his contention that the O.S. takes away 2 gigabytes of RAM from applications in order to use the high order bit doesn’t make sense. So I investigated.
The Apple documentation clearly states 31 bits was a hardware limit for addressing in the G4. I wouldn’t be skeptical of such a detail.
Anyway, I looked around the Apple documentation some more, in particular at what Tiger offers. It will be capable of addressing all 16 gigs of ram that the G5 architecture allows.
So this means, today, with Panther and a G5, you can write and compile a program to use 4 gigs, and tomorrow with Tiger, you’ll be able to write and compile a program to use 16 gigs.
Is it worth Adobe’s time to play around with the 4 gig capability? Is Adobe planning for the 16 gig capability now? You can bet Microsoft is hoping Adobe is not. These things are partly up the users. (Apple says Tiger will be here next year — and that’s the kind of corporate statement that bears a doublespeak analysis. But why does it matter to an Apple owner when Microsoft and Intel get there?)
This is a big opportunity for Apple, and they certainly know it.
But, of course, AMD’s Opteron-chip is here now and it can address a 48-bit space, a huge number. And Linux can support 64 gigs of memory. And so think of the possibilities if Photoshop could run under Linux?
I dunno about that. Both parties have motive to stretch the truth / facts to their favor, as both companies stand to lose money if they haven’t addressed some particular need or problem being discussed.
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