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Beyond the 32-bit RAM limit

Posted on 7 Aug 2009 at 15:01

Darien Graham-Smith explains the benefits of 64-bit memory

Flick through a recent issue of PC Pro and you'll see that most new PCs come installed with 2GB or more of RAM. It's easy to ascribe this to Windows Vista, which can be sluggish with less RAM, but if you look at the graph below it's clear that current RAM quantities fit a surprisingly regular growth curve that's been playing out since long before Vista came on the scene.

And if we extrapolate from the curve, we can predict that 4GB of RAM will be standard by late 2010 - just a year after the launch of Windows 7 - with 8GB becoming the norm two years later.

But what will all this extra memory do? The conventional wisdom is that installing more memory boosts performance, as the OS doesn't rely so heavily on slow disk-based virtual memory. In our feature Memory Stripped Bare, we found that upgrading a Vista system from 512MB to 2GB yielded a 14% performance improvement in our real-world benchmarks. But this was enough to minimise the effect of disk paging: adding more RAM beyond 2GB had almost no effect.

More Demanding Tasks

What about more demanding tasks? After all, in a few years we may commonly be working with ultra-high resolution images and high-definition video. To simulate this, we tweaked our standard Photoshop benchmark to run on the 32-bit and 64-bit versions of Photoshop CS4, rather than the 32-bit CS2. And we replaced our usual collection of four-megapixel photographs with a set of 50 14-megapixel images.

On systems with 3GB of RAM, this challenging test revealed no performance difference between 32-bit and 64-bit platforms, in both cases completing in 20mins 40secs. When we boosted the memory up to 8GB on the 64-bit machine and repeated the process it took... exactly the same time again. Clearly, the 32-bit RAM limit won't have much impact on photo-editing tasks for the foreseeable future.

Next we set up a demanding video task in Adobe Premiere Pro CS4: a 1080p input video was chopped up, reordered and spliced back together, with transition, motion and transparency effects. The resulting movie was then exported as an H.264 file in 720p format. On a system with 3GB the final render took 22mins 20secs; our 8GB system was faster, but only by 43 seconds. It seems video editors also won't need huge amounts of RAM for a while.

Yet there are specialist cases in which having 8GB or more really does help. If you're running an internet server, for example, or multiple virtual machines, it's possible to devour huge amounts of RAM. And as the amount of RAM in a typical PC continues to rise, applications will take advantage of increasing resources to offer new features, or faster (but more memory intensive) routines. There's no doubt that sooner or later 2GB will start to feel cramped.

For now, though, we'd advise against rushing out and buying a stack of DIMMs, as current desktop apps simply don't need vast banks of memory. By all means switch to a 64-bit OS - that way, you'll be ready to upgrade when it becomes useful. Until then, let RAM prices continue to fall until there's a reason to buy.

Author: Darien Graham-Smith

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User comments

This new site works very well in IE8 but not FF!

My Lenovo came loaded with 4gb ddr-800 (nice I thought) Vista HP-32bit (dumb) it never was fast with Vista, much faster in XP but XP couldn't access the 4gb either, neither actually does Win7 apparently do so - now is that because I need a 64bit OS to see it? If so why was I sold a machine with a 32bit OS in the first place?

By nicomo on 13 Aug 2009

I wouldn't worry

64 bit is more marketing at the moment as it driving sales. What is often overlooked is a 64 bit OS and applications can take up as much as double the memory space when running. The CPU cache is also effectively halved in size due to all the 64 bit pointers etc taking up twice the room, so you will lose some performance. You probably have more available memory with 3GByte on a 32 bit system than getting the full 4GByte on a 64 bit system. The 32 bit OS will also perform slightly better and have less issues with drivers and application compatibility.

To make 64bit worthwhile you need 6Gbyte or better and really need that much memory, most users do not and can quite happily use 2GByte.

By Phil_Z on 13 Aug 2009

Who runs just one application

While i agree that the benifits of 64bit for single applications is negligable, i would be amazed to see any 32bit 3gb system cope with the application sets i use on my 12gb 64bit system. i often run adobe premier pro cs4, photoshop cs4, superconvert, adobe auditions and a host of other editing software on my machine without noticing a performance impact. comapre that to the 32 bit system which strugles with just premier and super converter and you can see the true benifits of 64bit.

By Mccers on 14 Aug 2009

Who runs just one application

By Mccers on 14 Aug 2009

Who runs just one application

By Mccers on 14 Aug 2009

In Replay to Who runs just one application

Maybe 32bit systems are more efficient since they don't have to perform functions in triplicate

By subseb on 15 Aug 2009

motherboard chipset makes a difference

No information on what motherboard or chipset used for this test but it makes a BIG difference. Not all motherboards can access even > 3GB, e.g. intel 945P chipset, even when running a 64-bit OS. So obviously installing more RAM would show no performance differences. So what motherboard / chipset was used to make the claim that installing more RAM does not increase performance?

By XianQuin on 16 Aug 2009

"While i agree that the benifits of 64bit for single applications is negligable, i would be amazed to see any 32bit 3gb system cope with the application sets i use on my 12gb 64bit system."

Exactly, the only people that benefit from 64bit currently are those people who know they will, such as you. The average home or business user simply doesn't need more than 4GByte of RAM at this point in time.
If you have 4GByte sacrificing 1GByte to run a 32bit OS is going to be better than using a 64Bit OS just so you can claim you are using the full 4GByte as there is a cost involved running 64bit. The cost is that everything uses more memory being 64bit, so that 4GByte on 64bit is more like having 3 or perhaps even 2 GByte on a 32bit OS
To have the same free memory when moving from 32 to 64bit just like the number of bits have doubled, you need to double* your memory as well to just keep up, then add some to have in real terms more memory.

*It isn't quite like losing half the memory moving to 64bit as a lot of applications and services are still 32bit,, but the more applications moved to 64bit the more the memory is effectively half the size it would have been on a 32 bit Windows OS

By Phil_Z on 17 Aug 2009

Very poorly researched article

This article sucks. It's like a bad school essay, written by someone who obviously has no clue about the subject and who gives meaningless examples, e.g. "On a system with 3GB the final render took 22mins 20secs; our 8GB system was faster, but only by 43 seconds. It seems video editors also won't need huge amounts of RAM for a while." with no reference to any data set sizes. If the video was 43 seconds long then saving 43 seconds is 2x faster. This author needs to leave reporting of technical discussions to technically knowledgeable professionals.

By XianQuin on 19 Aug 2009

replying to Phil_Z

[quote]
you will lose some performance. You probably have more available memory with 3GByte on a 32 bit system than getting the full 4GByte on a 64 bit system.
[/quote]
--------------------------
[quote]
we tweaked our standard Photoshop benchmark to run on the 32-bit and 64-bit versions of Photoshop CS4, rather than the 32-bit CS2. And we replaced our usual collection of four-megapixel photographs with a set of 50 14-megapixel images.

On systems with 3GB of RAM, this challenging test revealed no performance difference between 32-bit and 64-bit platforms, in both cases completing in 20mins 40secs.
[/quote]

By Morphasella on 20 Aug 2009

EMM386.. come back, all is forgiven!

Some CAD systems, e.g. Autodesk Inventor, are quite a tight fit within the 3GB which is the max an app can have under 32-bit XP.

That said, I don't forsee any advantage in a 64-bit OS other than more RAM, and I do forsee compatibility problems.

Would it not be better/simpler to produce a patch like the memory-paging that was used long ago on DOS computers? Though this probably wouldn't allow any one app to use more than 4GB, at least you could then launch several 4GB apps.

By Anteaus on 21 Aug 2009

@Phil_Z -

[quote]
"If you have 4GByte sacrificing 1GByte to run a 32bit OS is going to be better than using a 64Bit OS just so you can claim you are using the full 4GByte as there is a cost involved running 64bit. The cost is that everything uses more memory being 64bit, so that 4GByte on 64bit is more like having 3 or perhaps even 2 GByte on a 32bit OS
To have the same free memory when moving from 32 to 64bit just like the number of bits have doubled, you need to double* your memory as well to just keep up, then add some to have in real terms more memory."
[/quote]

This is rather overstated as whilst it is correct, application code sizes will be larger due to the increased memory pointer size, it is a fallacy to assume that overall memory usage would be almost doubled from switching to 64-bit applications.

Typically application code constitutes only a small portion of the system memory - the majority of RAM usage is from data - including caches, graphics and other resources necessary for UIs, the display, audio and so on. Think Firefox for example.

There can be a similar argument made for program code - not all lines of code reference memory - especially for performance too.

Most users will not noticeably detect decreased memory availability if at all - in fact, it's only ever going to be an issue if all you do is run 2+GBs of poorly-compiler-optmized program code (excluding data resources!).

By fusioned on 1 Sep 2009

64bit is a requirement for a new computer

On a laptop you may get away with 2GB or 3GB because laptops are functionally limited by design. Open a few windows using either Firefox or IE8 and see how much RAM you are using. Do this on Vista while Outlook 2007 and a Word document is open and you have already used up ALL of your 2GB or most of your 3GB RAM. Play a video file and open an adobe file.
That thrashing sound that you are hearing is you hard disk drive being used all the time because you have ran out of RAM!

64bit optimized video editors are vastly superior to 32bit versions. Dont try to render a 1080p 1h video on a 32bit system with 3GB RAM!

By skgiven on 18 Sep 2009

4GB limit a sales myth

This article shows that it is a licensing issue not a physical one as seems to be the general opinion.
http://www.geoffchappell.com/viewer.htm?doc=notes/
windows/license/memory.htm

Remembering the old msdos days I would agree with it

By Sarcen on 22 Oct 2009

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