Creating ram disk to make OX run faster? $25 for secret?

Don't worry about it, worked with OS 9 -- but with OS Xs Virtual Memory scheme, anything moved to memory can be paged back out to the HD.

So a RAM disk can be moved back out to the HD anyway.

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Basically you create a 200 MB HD in RAM, copy an app to the RAM drive and run it from that RAM drive.

Under OS X something that might normally soak up 20MB of RAM now eats up 200MB of RAM -- making you access the drive all that much more.

RAMs bandwidth is 3200 MB/s while a drive operates around 50 MB/s -- so it works awsome for a database file you may want to play around with or a large file you want to manipulate and have RAM to burn.

 

Sun Baked is essentially correct, but he may be too kind to the idea of RAM disk on a Mac. The argument for RAM disk is based on ignorance of the memory map of the target OS. If you have more RAM than your OS can address directly, then RAM disk makes sense. This was possible back in the day before the 32-bit clean MacOS. In the case of MS-DOS, which could directly address only 64 KB, bank-switch up to 640 KB, and get to 1 MB through some kind of mumbo-jumbo, RAM disk gave greater benefits. However, with the advent of OSes such as MacOS X, Win NT and follow-ons, your OS can address directly every bit of RAM that you install--pardon the pun. Therefore, you are better served using your RAM as RAM rather than using it as emulated hard drive space.

 

I would be interested in this also. Imagine a G5 with 8 gigs of ram. You load OS X and a few programs on PC3200 RAM, geez... that thing would FLY!

obligatory..
imagine a beowulf of these!!!

 

As said, under OSX this borders on useless, as everything must come off the hard drive at some point, and you could well end up slowing the OS down if it ends up paging because your RAMDisk ate up too much space.

The only time a RAMDisk should speed anything up would be if you pre-loaded any apps into the RD when starting up, which would take a bit but they'd then load faster when launched. Of course, if you have that much RAM just launching them all at startup would have exactly the same effect, only with even less delay opening them later.

The only other situation would be with an app that was very bad at caching data and has a tendency to load something large off of the disk at a bad moment or tries to only write to disk when it should first be buffering to RAM. In these cases going through a RAMDisk would smooth out the bumps by overriding the program's RAM management, but that's of specific and limited value.

Here's very roughly how the OS actually does things, and why RAMDisks are mostly useless: You open a program. The program says, "I need data X". The OS loads data X into RAM. You later quit the program, which says "I don't need data X anymore". The OS keeps data X in memory, just in case. If you run out of RAM later, it tosses the unusued data to make room. But if that program says "I need data X", the OS already has it loaded, and so it's right there ready to go. This is one of the reasons apps launch faster the 2nd time.

Likewise, any well-written program will cache whatever it needs in RAM anyway; QT Player, for example, has a checkbox to preload an entire movie and hold it in RAM so it doesn't need to hit the disk to play it. Takes up a load of RAM, but it's fast.

 

Dont waist your money. If you want better performance, invest in some RAM.