I’ve tried to track this down from a number of places, but can’t get an answer. I’m assuming the same as CS3e, which is a little over 3 GB.
I’m getting ready to build a new MacPro and I need to decide how much RAM to add initially. I’m a Mac tech, so pretty good at building kick-but systems, but I don’t have CS4e yet, so can’t figure this one out for myself. I usually max out my systems, but I don’t think I can really utilize a full 32 GB of RAM with CS4 suite, but perhaps CS5. No sense in getting more RAM at this point in time, when I could use those dollars for good glass to take more pictures with! 😉
And FYI, real PS performance comes from using 10K rpm drives for startup/apps and a second one for Scratch.
I noticed major system speed increases when I passed 8GB and again when I passed 13GB. Even though PS may only be able to access 3GB, the additional RAM does not go to waste.
Respectfully – I asked a very specific question and neither reply answered it. I’m not looking for general counsel, which is why I didn’t go into more detail on what I am considering.
I meet almost no one whose system was really built to handle what they ask of it. I know they exist, but few invest the time to understand their software and it’s real needs and then invest in the hardware to make sure they have the resources to do well – what they ask of their system.
So – not to be rude – but I asked one simple question and I am only looking for an answer to that question.
Moving to fast startup and scratch drives will do more to impact overall performance than being RAM thin, or RAM adequate, or even RAM flush.
Unless you are running the Windows version (which can run in 64 bit and use greater memory), CS4 handles memory the same as CS2, which is why g linked to that CS2 article. Perhaps the question to ask now is, ‘what part of that article did not make sense?’ We can’t read minds.
The question is the subject of the post: How much RAM can PS CS4e use in Mac OS 10.5.x?
Without asking more questions about other software and/or peripherals I use, no one can suggest what amount of TOTAL ram I should have in my system – yet the initial replies went down that road. Been doing Mac tech support and color management and PS training for twelve+ years. I can do the rest of the math for my own needs. I just need to know how much PS CS4e can use now?
JJ – while what you say is true, the article is titled for CS2. It’s not titled CS2, CS3, CS4, so no reason for me to assume it still applies. It may, and I’m certainly not here to debate or question that. I was just looking for a straight answer from someone who has the software installed on a MacPro with more than stock RAM that can look in the PS prefs, and report what they see. Nothing more – just that.
Yep. My bad. I think its pretty safe to say 3 GB is the max ’till CS5. But as the original responders posted, you will see speed increases with more than 3 GB:
If you have more than 4 GB (to 8 GB), the RAM above 4 GB is used by the operating system as a cache for the Photoshop scratch disk data. Data that previously was written directly to the hard disk by Photoshop, is now cached in this high RAM before being written to the hard disk by the operating system.
CS4 is a 32 bit app.. just like v6, v7, CS, CS2, and CS3. The amount of RAM it can be allocated has not changed form previous versions.
Additional RAM installed in a system does not go wasted however. Just because Photoshop only accesses 3.3GB directly it does not mean that the OS can’t use an extra GB or three when writing scratch content, drawing UI windows, performing background tasks, etc.
If you’d get off your soapbox and read some of the replies you’ve been given you can easily deduce that this is what several people have posted.
Now.. feel free to continue to argue with replies you receive. I really wish I had a Light Grenade at times.
Actually – I’ve read all of the responses – and if people are honest – most of them require interpretation – including post 6. The answer is a number – it answers with words assuming I know what CS3 or CS2 used.
It’s clear this crowd would suggest the answer is 3072MB , which is what CS2 and CS3 could use.
If reply one had said that the thread would have ended right there. And if the Adobe article made it clear it applied as equally to CS4 as CS2, that too, would have helped. It didn’t.
I was trying to decide between 18 and 32 GB of RAM for my Mac Pro. Adding only 16GB up front saves me money for camera glass. I’ll add the second 16 GB closer to CS5.
The answer is more complicated than that, and the amount of RAM that Photoshop can directly access has indeed changed as of CS3.
Elementary computing math. Both Panther and Tiger, under which Photoshop CS3 was developed and released, are 32-bit operating systems.
The 232 limitation still holds for all 32-bit applications (minus overhead/application footprint 231).
Because one bit is reserved, the calculation has to be 231, which works out to 2147483648, and that’s why up through CS2, the Photoshop limit was around 2 GB as it was for any other applications because of the limitation imposed by the 32-bit OS.
In CS3, the Photoshop engineers devised a workaround to circumvent the limitations of the 32-bit OS to let it access about 3 GB. (There’s some overhead and rounding off.)
So, be thankful for the resourcefulness of the Adobe folks, rather than rant against the forces of nature and mathematics.
RC – thanks for the post. My brain was telling me there was some change between CS2 and CS3, but when I fired up CS2, it was asking how much of 3072MB I wanted PS to use, same as CS3 does.
I was thinking there WAS a difference between the two and that was the basis of my question regarding CS4.
I realize, on the surface all three are 32-bit – but that doesn’t mean that tweaking isn’t going on that may make more in fact usable by the program.
And, yes, ar, having plenty of RAM is the way to work when one plans to keep several apps open. On my creative system, a dual 2.7 GHz G5, 8GB RAM, I almost never see the beach ball and things happen quick. It also has a 10K rpm startup drive, which means that all system level virtual memory, which impacts OS and just about every app is able to perform at around twice the rate of stock drives.
Really looking forward to new system with 8 proc cores, 10K rpm drive for startup and second one for Scratch, Bridge cache, audio capture, etc. 18GB of RAM to start, move to 32 GB in a year or so, getting ready for CS5, which will likely be out in a couple of years.
Photoshop CS3 and CS4 CAN use more that 4 gigs of ram _IF_ in CS3 you install the VM Buffering plug-in. In CS4 it’s not needed. Then Photoshop CS3/4 will directly access just under 4 gigs (the limit is 4 gigs minus the application footprint which is about 700 MBs or sonot an exact number due to what Photoshop is loading such as textures, brushes, ect.) Thereafter, Photoshop CS4 (and CS3 with the plug-in) will use FREE RAM as the first primary VM in leu of scratch disk (which is much slower).
Tests have shown that over 8 gigs of free ram will have a very beneficial on performance and speed. NOTE: this is assuming 10.5.5, pretty sure that 20.4.x still can’t correctly use the VM plug-in without slowdowns).
This was _NOT_ the case with CS2 which was strictly limited to under 4 gigs…
Hopefully that awkward last paragraph does apply, even if the Macintosh is not mentioned in it, since the title of the Tech note is Optimize performance in Photoshop CS4 on Mac OS.
‘m getting ready to build a new MacPro and I need to decide how much RAM to add initially.
That is a lot easier question than the technicalities of how much RAM PS directly addresses. 8 GB RAM is IMO pretty much a logical minimum for a graphics Mac Pro, although 4 GB or 6 GB also do work.
MPs have 8 slots and memory performs best installed in sets of 4 identical DIMMs. So add 4×2 GB third party RAM initially if your budget is tight and you want best value initially, or 4×4 GB if you want to be able to someday max out at 8x4GB. Unfortunately 4GB-sized DIMMs still cost more per GB. 🙁
RAM performs best installed in 8s, not 4s. So 8 x 1, 8 x 2, or 8 x 4 will give you the best RAM performance in the current generation of MacPros. Testing was done at www.barefeats.com to bear this out. As a practical matter most people may not feel the difference, but that is what has been tested to be true.
I plan on adding four 4GB initially, putting me at 18GB, but will add another four 4 GB hunks* in time.
* What else do you call DIMMs with massive heat sinks in tow?!?
There’s actually an error in the technote wrt PS CS4 64-bit and the 8GB RAM limit. PS CS4 64-bit (running on a 64-bit OS) can use as much RAM as the system has. While I haven’t done this myself, one of the testers I worked with did allocate ~90GB of physical RAM to CS4 64-bit. More RAM = less disc access = faster performance.
I’ll see about getting that tech doc revised with the correct info.
CS4 (running on OS 10.5.x) will take advantage of all the RAM you have in your system as long as VM OS buffering is active (up to 32GB – I haven’t tested more than that).
Adam…as far as I can see, the "Goodies" optional Plugins folder only has the Bigger Tiles.plugin in it. Course, I’m not 100% sure that the "rewards download" for beta testers got an exact duplicate of the final GM disk (it is an ISO that "seems" like the GM of Extended). But I can’t find that CS4 installed the ForceVMBuffering.plugin in any of the plugin subfolders…
So, will the CS3 version work or do we need the CS4 version?
You find them in the Automate folder. Not in Extensions.
No, you don’t…the ForceVMBuffering is not anywhere in the Goodies folder from the installer and the installer did not install it anywhere in the CS4 plug-ins folder. If it’s in YOUR Automate folder, it’s because you put it in there…the ForceVMBuffering.plugin should be installed in the Extensions folder (not that it matter WHERE in the folders it’s installed, but it ain’t installed anywhere except in my CS3 plug-ins folder because I put it there).
I can’t get my hands on the shipping DVD right now, but if it is not included we’ll post the plug-ins for download on Adobe.com soon.
This is only an issue for CS4 users who want VM OS Buffering on 10.4.11. VM OS buffering is on by default with CS4 (and CS3) on 10.5.x, in which case users who want to disable it would want to grab the DisableVMBuffering.plugin.
I’ll also need to check to see if the CS3 plug-ins work with CS4, but I’m assuming they won’t.
Adam, the 3/21/07 ForceVMBuffering.plugin found in the "vm_buffering_opt_ext.dmg" listed as a download for CS3 posted 5/18/2007 <does> appear to work as expected in CS4 on my 10.4.11 PPC machine w/ 16GB RAM.
I haven’t compared the latest version of 9/4/08 with the CS3 version to see if one is better than the other speed-wise though.
Learn how to optimize Photoshop for maximum speed, troubleshoot common issues, and keep your projects organized so that you can work faster than ever before!
Related Discussion Topics
Nice and short text about related topics in discussion sections
