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RAM Charger 8 For Macintosh
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How does RAM Charger compare to RAM Doubler (virtual memory)?


(Tech0020A -- 06/02/98)


RAM Charger and RAM Doubler are very different enhancements.

Whereas RAM Doubler provides the same memory features as Apple's virtual memory (enabled in your "memory" control panel), RAM Charger is very different. A more in depth discussion of RAM Doubler, and explaination about its memory enhancement being the same as Apple virtual memory, is provided on the page "What is RAM Doubler (RD), and should I use it?"

Since RAM Doubler virtual memory is provides the same memory enhancement as Apple virtual memory, the real question is:

How does RAM Charger compare to virtual memory?

Because RAM Charger adds completely different functionality to your Mac than virtual memory, the only similarity is that each helps you accomplish more with less RAM. The real comparison is the difference: RAM Charger makes more efficient use of your memory without increasing it; Virtual memory increases your memory without making more efficient use of it.

Whereas vitual memory does not change the way your Mac works at all, instead simply increasing the amount of memory like adding RAM, RAM Charger brings new features to the Mac that are otherwise unavailable. RAM Charger provides each application with access to all free memory on your machine. Because of this, RAM Charged applications can grow and shrink in memory usage while they operate. Moreover, applications reserve only what they require at startup, yet do not run out of memory until all your memory is in use. They don't hog memory, nor do they run out of memory prematurely.

Without RAM Charger applications are limited to the amount of memory they start with - no more, and no less - no matter how much memory (real or virtual) the Mac has. The amount each application starts with is configured in the Finder's "Get Info" window. The memory dedicated to each application is visually apparent after the application starts by opening the Finder's "About This Mac" window. Once an application uses its starting memory, it is unable to use any more memory even though the memory may not be in use. So, it is common for Mac users to "Run out of memory" in an application, despite the fact that there is plenty of unused memory!

When is RAM Charger valuable?

RAM Charger's ability to remove the artificial "fixed" limitation is most valuable for any application that does not use the exact same amount of memory every time it is used. RAM Charger will allow you to start such applicaitons in a reasonable size, rather than an inflated provisional size, without worry that the application will run out of memory prematurely. By starting the applications in reasonable sizes, you will leave more memory for other applications and system operations.

In particular, applications in which you open and close documents tend to vary greatly in memory usage depending on how large the documents are, and how many documents you open. However, even applications that fluctuate small amounts can benefit since you do not need to provide them with extra precautionary reserves - just start them in what they require and RAM Charger will fulfill any extra requirements.

Because RAM Charger shares memory between applications in a more cooperative way, more benifit is gained the more applications you have open at the same time.

When is virtual memory valuable?

Virutal memory is valuable when you can't run the applications you need to run regardless of how efficiently your memory is used. As a result, it is our opinion that you should try RAM Charger first to see if you can accomplish your goals using real memory (just RAM), before resorting to virtual memory which substitutes slower techniques to provide "memory" beyond your real RAM.

Virtual memory is also valuable for anyone running a PowerMac using PowerMac native applications. This is discussind in great detail on the page "Should I use VM?"

Why don't people call RAM Doubler "virtual memory"?

The answer would be "marketing".

Since the original implementations of Apple Virtual Memory were so poor, a stigma developed about the term "virtual memory". This is unfortunate, since virtual memory has long been used and accepted without such a stigma in both Unix and Windows - due to better implementations.

Our specualtion is that Connectix did not want the term virtual memory to be associated with their product, despite the fact that it is virtual memory. It is tru that RAM Doubler uses an alternative method for "backing storage", however this is not releavant. It employs virtual addressing, and provides functionality no different than any other virtual memory implementaion.

Instead, Connectix took a term "extended memory", which is clearly defined to be something totally different in the DOS PC environment, and redefined it for their own purpose. Despite the fact the proper term virtual memory existed, uninformed users and reviewers adopted the new term.

Connectix marketing was successful. Very few people understand that RAM Doubler provides no features over Apple Virtual Memory, and many confuse its features with RAM Charger. We thikn it only proper that users understand that RAM Doubler is virutal memory.


RAM Charger and virtual memory (Apple or RAM Doubler) are very different methods of making most of your Mac. RAM Charger works on a per application basis to make the most efficient use of your memory, and vitual memory increases the amount of memory without puchasing more hardware. Since these are fundamentaly different, the two techniques can be used together to obtain the most from your Mac. Depending on your usage, you may wish to use virtual memory to supplement with RAM Charger.


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Copyright © 1995-98 Jump Development Group, Inc. All rights reserved. Jump, OptiMem, RAM Charger, and More About This Mac are trademarks of Jump Development Group, Inc. Apple and Macintosh are registered trademarks of Apple Computer, Inc. All other trademarks are the property of their respective holders.