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View Full Version : This "Compressed Memory" is a big deal


C64
Jun 11, 2013, 10:07 AM
Check out OSX_Mavericks_Core_Technology_Overview.pdf (http://images.apple.com/osx/preview/docs/OSX_Mavericks_Core_Technology_Overview.pdf) via http://www.apple.com/osx/preview/advanced-technologies.html.

They talked about this feature for a bit in the Keynote, but after reading the specs I'm getting the impression that this is a pretty important feature that will actually have a big impact on usage.

Compressed Memory keeps your Mac fast and responsive by freeing up memory when you need it most. When your system’s memory begins to fill up, Compressed Memory automatically compresses the least recently used items in memory, compacting them to about half their original size. When these items are needed again, they can be instantly uncompressed.

Compressed Memory improves total system bandwidth and responsiveness, allowing your Mac to handle large amounts of data more efficiently. Through use of the dictionary- based WKdm algorithm, compression and decompression are faster than reading and writing to disk. If your Mac needs to swap files on disk, compressed objects are stored in full-size segments, which improves read/write efficiency and reduces wear and tear on SSD and flash drives. The advantages of Compressed Memory include the following:

• Shrinks memory usage. Compressed Memory reduces the size of items in memory that haven’t been used recently by more than 50 percent, freeing memory for the applications you are currently using.

• Improves power efficiency. Compressed Memory reduces the need to read and write virtual memory swap files on disk, improving the power efficiency of your Mac.

• Minimizes CPU usage. Compressed Memory is incredibly fast, compressing or decompressing a page of memory in just a few millionths of a second.

• Is multicore aware. Unlike traditional virtual memory, Compressed Memory can run in parallel on multiple CPU cores, achieving lightning-fast performance for both reclaiming unused memory and accessing seldom-used objects in memory.

Swapping to disks has always been an important reason for things to feel slower. That's why everything seems so fast on machines with an SSD, because even if it needs to swap, writing to the SSD is way faster than to traditional HDs.

With Compressed Memory it needs to swap less frequently, swaps compressed objects, and now that the MacBook Airs (and I'm sure the MBP and the rest of the Mac line-up will follow) have PCIe SSDs (http://www.anandtech.com/show/7058/2013-macbook-air-pcie-ssd-and-haswell-ult-inside) with "read/write performance of nearly 800MB/s", these things are going to fly!

thejadedmonkey
Jun 11, 2013, 10:13 AM
I must say, after all of the lack-luster OS X updates, 10.9 is looking to be huge for anyone who isn't part of the hipster "I need a mac for checking my facebook at starbucks" crowd.

w0lf
Jun 11, 2013, 10:20 AM
I must say, after all of the lack-luster OS X updates, 10.9 is looking to be huge for anyone who isn't part of the hipster "I need a mac for checking my facebook at starbucks" crowd.

Actually I think it will be really nice for that group of people that don't really know how to use a computer and have 4Gb of RAM and just keep opening things without ever closing anything.