I'm at 53 MB used of 1 GB total swap after three days of uptime, while on 10.8 I would go far over that within minutes of startup (usually topping out at ~10 GB total after a day or two), so something does appear to have changed.

I run several virtual machines on my 8 GB MBP and I have never seen swap issues. Are you sure your problems are actually caused by swap?

"purge" doesn't touch swap, it discards disk cache. Its use (according to the man page) is to simulate cold boot disk performance. The command has no use for memory management, because disk cache is automatically discarded when free memory runs out.

This sounds more like an issue with an app (or a kext) consuming way too much memory than any innate OS-level issue with paging. Activity Monitor and/or top can be useful in figuring out what the heck is using up all that memory. Xcode can use a really surprising amount of memory sometimes but it's not going to just gobble up 20GB of pageable VM.

I was just about to say the same thing - it's stunning how much faster/smoother it is.

The new way Multi Display works is also much better than the old way, Full Screen Mode is actually really useful now.

If that battery life improvement is representative of general use, it is another indicator that they really are pushing for energy efficiency. The first one, for me, was https://developer.apple.com/osx/whats-new/, where the top item for "develop for OS X Mavericks" is "Energy Saving", not any of the new libraries whose coolness one can demo in a few minutes.

Apple increased the available video memory on the retina machines from 768MB to 1GB. The difference is profound. I was concerned about being stuck with nothing but an HD4000 but I'm very content with everything now.

you get only 2.5 hours on MBP Retina !?!?

Thank you so much, we have Adobe suite running on our machines and I was tempted to upgrade! Thanks so much :)

Best resource for keeping up with these issues? I used to use Macintouch but I don't really trust that it gets all the user reports it used to.

Has anyone tried Adobe CS5.5? Any problems?

And put pressure on app developers not to be on that list without reason. glances with annoyance at the Twitter app

Upgrading generally works great with OS X; generally the upgrade process blows away the system/OS files and leaves your stuff untouched. In the normal case, "your stuff" is well compartmentalized away from system files so stuff works nicely.

With that said, as a developer sometimes it can be handy to do a clean install. For example, if you have any custom kernel modules, these will certainly be blown away in an upgrade. Additionally, developer tools installed in /usr/ can be interfered with, and in general the probability that something will be incompatible/broken is a bit higher.

I've read posts from folks who started at 10.1 and upgraded all the way to 10.8 without any issues.

I was fine with just upgrading except for Lion -> Mountain Lion. A lot of little nitpicks were fixed after I did a clean install.

I'm not experiencing any real change in battery life on my specced out 15" retina. Got ~5 hours before 10.9, get ~5 hours on 10.9. Makes me kind of wish I'd gone for the base CPU and saved money and battery life.

13" MacBook Pro retina.

Probably get a solid and consistent extra hour. From 6 solid hours to 7. I can push to 9 now if I lower the brightness and don't browse the web.

2009, 13" MBP. Went from ~2.5 hours up to ~4hours

I'm not noticing much of an improvement on my mid-2011 MacBook Air (< 6 month old battery, 145 cycle count). The fact that the battery life indicator shows applications that are using significant amounts of energy has made me more aware of which applications are sucking away my battery life, however.

I haven't run mine on battery much since upgrading; but as you might expect I feel like my fans run less, which is much appreciated. MacBook Air 11", Mid 2012.

2013 13" MBA (with i5). I'm getting more or less the same. 7-9 hours under normal usage. Up to 10-11 under very light load.

2012 Retina MacBook Pro. An extra hour.

2012 Macbook Air 11"

Last year i7 MBA went from ~2.5h -> ~3.5-4.5h

It does. It auto installed when I ran IntelliJ.

I believe it does.

You want OSX to keep network connections active while asleep? It seems to me that going to sleep means not actively doing anything.

The most common solution to this problem is to use tmux or screen, or just disable sleep.

you could use http://mosh.mit.edu/

It may just be more aggressively sleeping, as opposed to just turning the screen off. You can change this in power management settings.

I wonder if iTerm2 could be patched to support the PowerNap functionality - and so send SSH keepalives whilst the system slept (assuming of course your underlying network substrate didn’t change).

autossh is great, too if mosh doesn't fit your needs.

The next Apple press event is October 22nd. iPad-centric, but also expected to include Mac Pro pricing/availability, so probably Mavericks release as well...

I expect it will be released on the 29th of this month given that last year Apple released Mountain Lion the day after their earnings call.

I'd suspect it is limited to Cocoa stuff, so GUI only. It should be controllable via a setting anyway.

It may be worth explicitly restricting the tether connection to IPv4 only; have seen similar things where an ISP has something that looks like a working IPv6 setup but isn't.

They shouldbe exactly the same barring any showstopper bugs that get uncovered in the GM.

You have to fresh install developer releases while you can just upgrade to public release.

I totally agree with you but folks from the 80s said similar things about computing in the 90s. :) I can only imagine what the folks from the 70s would say. Like another poster said, it's not ALL bloat- there are lots of memory-hungry things going on in the background for user convenience that would have been unacceptable tradeoffs 10-20 years ago (in terms of how much system resources are consumed vs. the utility and convenience provided to the user), but on modern hardware those tradeoffs are less meaningful, and things that might have seemed wasteful 10 years ago become practical to do. I think a lot of it also from more and more graphics resources needed per app (high resolution images for UIs can consume an absurd amount of memory), as well as many apps being much more aggressive about caching stuff in memory for snappier response times (web browsers, or any kind of media-centric application). It seems inevitable that as memory gets cheaper, the average machine has more memory, and as the average memory of the average machine goes up, the perceived cost of memory consumption goes down, leading application (and OS) developers to figure out more and more ways to use all of that memory. It's a vicious circle (or a virtuous one, or both).

Modern OSs do a lot in the background that OSs in the 90s did though. For example, indexing and scanning every file on your hard drive so I can find a document that contains a certain word or phrase in a few seconds.

Actually, unofficially, the older iMacs support 6 GB (4+2) since the first aluminium iMac (mid 2007, I think)

I bought a 4 GB DDR2 DIMM for my Dad's mid 2007 iMac, installed it together with a 2 GB DIMM and it has been running non-stop for almost a year now, without any problems. DDR2 is now a bit expensive, due to being old, the 4 GB DIMM cost me around 50$ on eBay.

Mavericks adds ram compression. I don't know if it will turn out to be just a gimmick. I have been testing on a 2009 iMac with only 2GB ram w/ Intel SSD and it does just fine. Compressing 200-300MB when I check Activity Monitor.

On a mid-2010 iMac with 4GB I find it snappier than 10.8

Have you thought about adding an SSD?