# Is there a feature like 'ReadyBoost' in Mac like in Windows 8?



## tompatrick (Oct 14, 2011)

Hi All, 

Is there any way to use a USB free space as an additional RAM in latest Mountain Lion or any Mac OS? This feature exist in Windows 8 and sounds cool. Do Mac have 'ReadyBoost'.


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## CanadaRAM (Jul 24, 2005)

ReadyBoost was a dismal failure in Windows The problem with the idea is that USB Flash sticks are way slower than hard drives, and hundreds of times slower than RAM memory. This is both because USB is poor at bandwidth and a hog on CPU resources, and because affordable level Flash memory chips are very slow to respond, particularly to small writes.

Mac OSX manages its own memory in the background by using space on the boot hard drive as a virtual memory scratch or swap disk. You do not have to do anything to improve on it, it is inadvisable to try to mess with OSX's memory management at all.

If you want the theoretical maximum performance, first add real RAM. 

If you have enough RAM - that is, more real memory than your software and data are using - then you have no memory slow downs at all (and adding more above that level actually won't improve things, it would just raise the bar on how many programs you can multitask before running out of RAM)

Then assuming that you have increased the real RAM to the most the machine can handle, then you can use a faster drive, such as a SSD as your boot drive (where the VM swap files live). This will improve the virtual memory read and write performance.

What about assigning the VM Swap file to a different, faster drive? This could be done in OSX 10.4 and below, but Leopard and Snow Leopard changed things and made it very non-trivial to do. I haven't seen any evidence that it is even doable in Lion or Mountain Lion.

The technique is valid though for heavy Photoshop users. Photoshop (and some other programs) manage their own memory, and you can assign a different drive for *their* swap files. The idea is to use a drive that is NOT being used by programs, data or the OS swap files so that Photoshop and OSX do not arm-wrestle for control of the drive.


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## eMacMan (Nov 27, 2006)

Again a very simple Terminal command can help you determine if you are short on RAM.

Open Terminal found: HD>Application>Utilities>Terminal

Type: top
Then hit return or enter.

This will return a fair bit of information. In the paragraph right at the top look for this line:
VM: 109G vsize, 1041M framework vsize, 33201(0) pageins, *0(0) pageouts*.

Pageins can be very high. What you need to look at is pageouts. Ideally pageouts should be 0(0) even if you have been using the computer for a good stretch and keep a couple of key applications open.

If the number of pageouts is not very close to zero, then the computer will see a performance boost by adding RAM. If consistently 0(0) save your money.

You can simply quit Terminal when you have the info you need, ignore the warning about terminating processes.


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## broad (Jun 2, 2009)

or you can just open activity monitor and look at the pageouts there

i would suggest that anyone asking a question like the OPs should probably avoid terminal.


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## eMacMan (Nov 27, 2006)

It is unlikely any one simply typing in the 'top' command in Terminal would do any real damage to themselves. In fact it may well be the very best way to introduce someone to the usefulness of Terminal.

FWIW the activity monitor shows the size of pageouts rather than the number. I find the latter a more useful reference point as a single large pageout would not be sufficient reason to recommend a RAM upgrade.


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## CubaMark (Feb 16, 2001)

Jeez... my pageouts are running at 2.5gb. Let's see... diapers for the baby, or new memory for my MBP? Decisions, decisions....


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## MacUnited (Nov 1, 2009)

CubaMark said:


> Jeez... my pageouts are running at 2.5gb. Let's see... diapers for the baby, or new memory for my MBP? Decisions, decisions....


It all depends.. for example, how old is the baby?


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## Anonymous_5 (Feb 2, 2015)

I have a 2014 11' Macbook Air w/ max ram (8GB). With "top," this is what comes up for VM

VM: 681G vsize, 1063M framework vsize, 921194(0) swapins, 1017977(0) swapouts.

As you can see, not very good for "swapouts" so I would love to have a ReadyBoost alternative for mac. 

Has anybody found one?


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## CubaMark (Feb 16, 2001)

You may find it better all around to adjust your computing habits. Which apps do you use on a regular basis? How many apps are running at any given time (Command-Tab to check). The fewer the programs that are running, the less need for page ins/outs.

I constantly (infuriatingly) encounter people who came over from Windows, and have yet to grok that closing an application window (red light) does *not* quit the program. One person in particular, when calling me for help because her system is slow, is always amazed to discover that she has between 8-12 apps open (Photoshop, Aperture, Word, Safari, Scanning software, Mail, etc.).


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## Anonymous_5 (Feb 2, 2015)

I currently have 4 apps open - Safari (5 Tabs), Mailbox, Pages, and Terminal for checking VM.

Current: VM: 648G vsize, 1063M framework vsize, 925266(0) swapins, 1026551(0) swapouts.

I really don't know what else to do.


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## CubaMark (Feb 16, 2001)

Something's messed up there, man.

I'm on a mid-2014 Retina MBP 13" with 8 gigs of RAM. I have Safari, Terminal & Mail open. Heres' the Terminal result:

*M: 541G vsize, 1063M framework vsize, 830(0) swapins, 3451(0) swapouts.*

My performance is fine - no slowdowns, hiccups, etc.

Running Yosemite 10.10.2


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## IllusionX (Mar 10, 2009)

That's interesting. i have Firefox 7 tabs, mail, iTunes, skype, iMessages and terminal open.

VM: 553G vsize, 1065M framework vsize, 0(0) swapins, 0(0) swapouts.

16gb of ram on a 2011 MBP.


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## SINC (Feb 16, 2001)

Late 2013 MBP i7 2.6 Ghz 16 GB RAM with Safari, Mail, iMessage, Terminal and Activity Monitor open:

VM: 685G vsize, 1064M framework vsize, 0(0) swapins, 0(0) swapouts.


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## eMacMan (Nov 27, 2006)

Looks like they have eliminated Page ins. The swap-ins would seem to be the other end of the swapped out bits being brought back into memory.

What does the "top command" show in the newer systems?


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## cor (Jan 26, 2015)

*pageouts*

VM: 112G vsize, 1043M framework vsize, 44029(0) pageins, 0(0) pageouts

2009 mini 8GB 10.6.8 firefox, mail, temp, SMCfan, little snitch running.

will add photoshop and GB running- if high pageouts will post again


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## SINC (Feb 16, 2001)

eMacMan said:


> Looks like they have eliminated Page ins. The swap-ins would seem to be the other end of the swapped out bits being brought back into memory.
> 
> What does the "top command" show in the newer systems?


Mine shows the very same thing.


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## eMacMan (Nov 27, 2006)

cor said:


> VM: 112G vsize, 1043M framework vsize, 44029(0) pageins, 0(0) pageouts
> 
> 2009 mini 8GB 10.6.8 firefox, mail, temp, SMCfan, little snitch running.
> 
> will add photoshop and GB running- if high pageouts will post again


Your Page-outs are at zero it does not get any better than that.


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## cor (Jan 26, 2015)

eMacMan said:


> Your Page-outs are at zero it does not get any better than that.


Si 
opened photoshop and Garage Band with song running in GB-- same-----0 pageouts


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