Q: Upgrade to OS X 10.8.4 made system slow

I had to replace the harddrive! I'm picking it up tomorrow. I'm assuming they tested it but I'll let you know when I get it back. It's just strange we had same problem, same day durring an upgrade on same system!

does VMWare invokes even if its not opened?

Yes.

I noticed a similar problem on our iMac and MacBookProRetina. Also, apps and the system started to crash occasionally. Clearly there's a bug in 10.8.4. The slowness is quite noticeable.

I have solved my speed problem on my MacBook Pro.  I had been using a 15" Mid-2010 MacBook Pro until about a month ago when I updated to a 15" Mid-2012 (It was a clearance item).  I decided to update to 10.8 after a few weeks and speed dropped of on the new machine as soon as I did.  The 2012 was slower than the old one!  The new computer with 10.8 was often unusable it took so long to open anything.  I find I am mostly in battery mode- I charge it at night and run off battery during the day. But, I noticed that I am getting PHENOMENAL battery life. So I checked the Energy Saving settings.  Automatic Graphics Switching was enabled.  I turned this setting off and now the machine SCREAMS!  I imagine battery life will drop but I don't care, I cannot use the machine at all with the slower graphics mode enabled.  Thanks Apple....for nothing.

Same here, I am on a MiniMac 3.1 and went from 10.7.x to 10.8.5.  Many things just seem to go much slower. I have to wait wait wait for stuff to open. When I'm expanding a zip I have to wait many seconds before I can approach my Finder menu. Also when I do an info on my devices it takes loads of time before it calculates folder sizes. Much longer than in 10.7. Also compiling stuff seems slower.

I don't believe my harddisk is suddenly dying from excactly the same moment I upgraded  with a fresh install, where  more users notice these speed issue as well. Too much coincidence, right? I really don't know yet, but there has to be a reason..

I have to ditch 10.8.5 and go back to 10.7.x to figure it out (assuming my drive is not messed up now). I might post my results here.  Annoying..

Cheers

So the machine was reasonable fast after I turned off the graphics switching but after a week of use it still seemed sluggish.  I was not thrilled.

I hate to say it, but I took the plunge and upgraded the ram.  I went from 4GB to 16GB.  It's now the fastest MacBook Pro in the world.  It went from unusable Mac OS 10.8 crap to blindingly fast Mac OS 10.8.  It literally opens Word and Excel in a single second.  I have never had a computer this fast. I've never seen anything like it.  Admittedly this is a reasonably fast machine but I have owned at least 20 Macs since 1989.  Easy.  None have been this fast. 

BUT this is a work machine and I can make my work pay for the ram (~$200).  I am a little disappointed in Apple.  4GB is unusable.  They should make that a caveat of an upgrade.  I don't know about  8GB but you should not even be allow to install the upgrade with 4GB.

Shame on you Apple.  But guess what, I bought the ram from crucial.  So Apple didn't make a dime on it. I doubt it will impact their stock price...