iMac slow since upgrade to El Capitan

Similar Questions

• Why my iMac run slower after upgrade to El Capitan?

  Why is my iMac (27 inch, mid 2011) (processor 3.1 GHz Intel Core i5, memory 8 GB 1333 MHz DDR3, chart AMD Radeon HD 6970 M 1024 MB, GB 999,35 885,37 GB free storage capacity) slow start when you turn on the computer and run more slowly since upgrading my OS to OS X El Capitan 10.11.4 version?

  Download EtreCheck and post the report.

  

• Printing problems since upgrading to El Capitan

  Two weeks ago, that I've upgraded to El Capitan. Since then I was able to print from Adobe Acrobat or Microsoft Office programs. I use my Macbook for business purposes, and there is downtime with my work on this issue. This has nothing to do with printer drivers that I can't print to PDF either.

  I've used nothing helps Apple telephone support. I went to an Apple genius bar and they could not understand either. They have wiped my phone, and then I went home and restored the time upward from the standby machine. The problem was still there. So I uninstalled Microsoft office (last resort recommended by technician at the genius bar) and reinstalled. The problem is still there, and worse yet the Outlook is freezing. I rang a repairer of random computer company this morning specializing in Macs. They said they couldn't help me because they would only do what I've done. My Macbook Pro is just a few years, and now I'm looking down the barrel of the purchase of a new laptop - all because I upgraded to El Capitan!

  Troubleshoot printer on your Mac - Apple Support

  cant - print.html http://www.Macworld.com/article/2029528/Mac-Troubleshooting-What-to-do-When-You-

• HP Photosmart 7515 will not print since upgrading to El Capitan.

  I can't print with my HP Photosmart 7515 since the upgrade to El Capitan 10.11.1... I went to the HP site and installed only

  I solved the problem by resetting the printers and then adding the printer to the back.  Everything seems to work now.

• I can't sign in iMessage since upgrading to El Capitan - Suggestions?

  I can't sign in iMessage (Macbook Pro, early 2011) after upgrade to El Capitan 10.11.1 OS x 10.8.5. I have reset the passwords for my two Apple ID, out of the iCloud, signed and still cannot connect in iMessage. Diagnosis: "year error occurred during authentication.  All other applications (and machines, see below) with iCloud connections & shared data work without problems. Machine also crossed several reboots at least two resets of LANDAU. Any suggestions for next steps?

  The same update of the iCloud OS X 10.8.5 log 10.11.1 and subsequent out / in the sequence was repeated on my other Macbook Pro (mid-2012).  iMessage balls in and functions properly in this regard.

  My iPhone 6 + wife 5s and iPad Mini 1st generation (all with the same Apple ID & iOS 9.1), either have no problem with iMessage. Two Macbook pros are running 16 GB of RAM drives, backup of OWC data with the 480 GB SSD boot in original position of HD floppies and mechanical in the optical Bay. All devices are on the same time zone time, selected auto (CST).

  Updated - repair of Ran in Keychain Access.  Ran disk first aid utility.  Restart in Mode safe and by logging in to my account resulted in functional iMessage.  After restarting mode Normal iMessage remained functional.  A VICTORY.

  RT-Jhnsn

• iMac too slow after upgrade of El Capitan

  I get a lot of beachballing and slow start.

  Etrecheck said that protec6b is obsolete in the Yosemite OSX. What and how do to this day.

  com.Apple.csrutil.report.plist [failure]

  [loaded] 42 tasks Apple

  [failure] com.adobe.ARMDCHelper blah blah blah (2015-10-26)

  and backup too small (it is disconnected for now)

  Everything is green and or loaded

  We use the creative cloud Adobe Photoshop, Lightroom and Acrobat

  And Microsoft Office 365 for small businesses

  There is a Wacom tablet and a mouse, the keyboard and the trackpad.

  16 GB of RAM, of which half is free and half used with 1.5 GB of caching

  The usual java, Silverlight, flash, google earth and plugins for SharePoint (for office 365)

  No other software from third-party manufacturer, ladies of virus or cleaners.

  Takes forever to get a cursor active when he wakes and him asking to much Gets a beachball for 30 to 60 seconds or more. even fill out a form online has a delay from the moment wherever you type until it appears online. Unusual since we are on a fiber optic connection and a PC that connects to a computer on a remote server in California virtual works very well with no delay at all.

  How do paste you in the results?

• Why am I messages DNS error since upgrading to El Capitan?

  Since I upgraded my OS to El Capitan I was making (Yahoo Search page) DNS error pages when I use an Internet link to leave my email to another site. Its pretty boring and I have to use Safari where it happens. I like FireFox, but if I can't solve this problem I will be forced to stop using it. Help, please. Thank you, Michael.

  You might have installed something more. On Mac, this problem is associated with some extensions Spigot, especially one named Searchme.

  Open the page modules using either:

  • CMD + SHIFT + a
  • "3-bar" menu button (or tools) > Add-ons

  In the left column, click Extensions. Then on the side right, remove or disable Searchme - and anything else that you don't need, like all the other Spigot/MyBrowserBar extensions. Keep in mind that all extensions are optional and none is included with Firefox when you get it first.

  Often, a link will appear above at least an extension disabled to restart Firefox. You can complete your work on the tab and click one of the links in the last step.

  Is that what helps you regain control?

  This could be the tip of an iceberg of malware. When you install free software, you often get the options grouped under silence. I don't know the best way to 'clean up' a Mac of these elements, but you may want to consider the issue.

• Problems since upgrade to El Capitan

  Hello

  I bought an iPhone 6s and was on my MacBook Pro (2.53 GHz Intel Core i5 memory 8 GB) happy on OSX 10.7.5 but iTunes is not sync with iPhone 6s (Thx Apple!).

  So I had to upgrade and did on 10.11.5.

  Since then, whenever I restart my computer, it loses my iCloud ID, and I have to reset it as the first time. The dock must be reset as well. All the files on the desktop are in the position as I did nothing (I put a file to the trash and he exactly reappeared on the office where he was).

  It turns me crazy...

  Any help please?

  THX

  Ernst

  try to create a new account administration and this account, set up boot and reboot again

  is the same behavior?

• Constant beach ball since upgrade to El Capitan

  Hello

  I use a middle of the retina 2014 MBP with 16 GB of ram and a 512 GB SSD, the machine would never cause me problems or failure until I updated to El Capitan.

  Now I am constant beach balls gets when I use the machine, it is sometimes finder which crashes, or Safari, whenever the accident lasts 5-10 minutes until the BONE is still sensitive. I can switch between applications, but can't do anything with them, force quit does not work until after the accident.

  I was hoping that I could go down with time machine, but my previous backups seem to have disappeared, so I only have the backups I've made since the update to El Capitan, so now my only options are to find the source of accidents or wipe my machine and do a clean install.

  I hope someone can help me to get to the bottom of this issue. I tried to run in safe mode and everything works well, I tried to connect as a guest user but accidents still happen so it seems to be a problem with OS.

  I ran EtreCheck and the results are below

  EtreCheck version: 2.9.9 (260)

  Report generated 2016-03-14 16:27:30

  Download EtreCheck from https://etrecheck.com

  Time 03:25

  Performance: good

  Click the [Support] links to help with non-Apple products.

  Click [details] for more information on this line.

  Click on the link [check files] help with unknown files.

  Problem: Beachballing

  Hardware Information: ⓘ

  MacBook Pro (retina, 13 inch, mid-2014)

  [Data sheet] - [User Guide] - [warranty & Service]

  MacBook Pro - model: MacBookPro11, 1

  1 3 GHz Intel Core i7 CPU: 2 strands

  16 GB RAM not extensible

  BANK 0/DIMM0

  OK 8 GB DDR3 1600 MHz

  BANK 1/DIMM0

  OK 8 GB DDR3 1600 MHz

  Bluetooth: Good - transfer/Airdrop2 taken in charge

  Wireless: en0: 802.11 a/b/g/n/ac

  Battery: Health = Normal - Cycle count = 72

  Video information: ⓘ

  Intel Iris

  Color LCD 2560 x 1600

  L206W 1680 x 1050 at 60 Hz

  Software: ⓘ

  OS X El Capitan 10.11.4 (15E61b) - since the start time: 5 hours

  Disc information: ⓘ

  APPLE SSD SM0512F Disk0: (500,28 GB) (Solid State - TRIM: Yes)

  EFI (disk0s1) < not mounted >: 210 MB

  Recovery HD (disk0s3) < not mounted > [recovery]: 650 MB

  Macintosh HD (disk 1) /: 499,05 (Go 395,62 free)

  Storage of carrots: disk0s2 499.42 GB Online

  USB information: ⓘ

  Apple Inc. Apple keyboard / Trackpad

  Apple Inc. BRCM20702 hub.

  Apple Inc. Bluetooth USB host controller.

  Verbatim Portable USB Drive 500,11 GB

  EFI (disk2s1) < not mounted >: 210 MB

  Backups Time Machine (disk2s2) Volumes/Time Machine backup: 499,76 (Go 93,44 free)

  Apple Inc. IPhone.

  Lightning information: ⓘ

  Apple Inc. Thunderbolt_bus.

  Thunderbolt of Apple Inc. to Gigabit Ethernet Adapter

  Guardian: ⓘ

  Any where

  Unknown files: ⓘ

  / Library/LaunchAgents/com. Oracle.mydesktophelper.plist

  / Library/LaunchDaemons/com. Oracle.mydesktopservice.plist

  2 unknown files found. [Check files]

  Kernel extensions: ⓘ

  /Applications/transmit.app

  com.panic.TransmitDisk.transmitdiskfs [no charge] (4.0.0 - 10.6 SDK - 2016-02-12) [Support]

  /Applications/zoom.us.app

  zoom.us.ZoomAudioDevice [no charge] (1.1 - SDK 10.8 - 2016-02-12) [Support]

  / Service.app incompatible software/Parallels

  com.parallels.kext.prl_hid_hook [no charge] (6.0 11822.604190 - 2013-10-24) [Support]

  com.parallels.kext.prl_hypervisor [no charge] (6.0 11822.604190 - 2013-10-24) [Support]

  com.parallels.kext.prl_netbridge [no charge] (6.0 11822.604190 - 2013-10-24) [Support]

  com.parallels.kext.prl_usb_connect [no charge] (6.0 11822.604190 - 2013-10-24) [Support]

  com.parallels.kext.prl_vnic [no charge] (6.0 11822.604190 - 2013-10-24) [Support]

  / Library/Extensions

  org.virtualbox.kext.VBoxDrv [no charge] (4.1.8 - 2016-03-09) [Support]

  org.virtualbox.kext.VBoxNetAdp [no charge] (4.1.8 - 2016-03-09) [Support]

  org.virtualbox.kext.VBoxNetFlt [no charge] (4.1.8 - 2016-03-09) [Support]

  org.virtualbox.kext.VBoxUSB [no charge] (4.1.8 - 2016-03-09) [Support]

  / System/Library/Extensions

  com [no charge]. Cycling74.driver.Soundflower (1.5.1 - 2016-03-09) [Support]

  com.devguru.driver.SamsungComposite [no charge] (1.2.48 - 10.6 SDK - 2016-03-09) [Support]

  com.Wacom.kext.wacomtablet [no charge] (6.3.6 - SDK 10.8 - 2016-03-09) [Support]

  com.wdc.driver.1394HP [no charge] (1.0.9 - 2016-03-09) [Support]

  com.wdc.driver.USBHP [no charge] (1.0.11 - 2016-03-09) [Support]

  /System/Library/Extensions/ssuddrv.kext/contents/plugins

  com.devguru.driver.SamsungACMControl [no charge] (1.2.48 - 10.6 SDK - 2012-05-18) [Support]

  com.devguru.driver.SamsungACMData [no charge] (1.2.48 - 10.6 SDK - 2012-05-18) [Support]

  com.devguru.driver.SamsungMTP [no charge] (1.2.48 - SDK 10.5 - 2012-05-18) [Support]

  com.devguru.driver.SamsungSerial [no charge] (1.2.48 - 10.6 SDK - 2012-05-18) [Support]

  Startup items: ⓘ

  VirtualBox: Path: / Library/StartupItems/VirtualBox

  Startup items are obsolete in OS X Yosemite

  Launch system officers: ⓘ

  [loaded] 6 tasks Apple

  [loading] 156 tasks Apple

  [operation] 75 tasks Apple

  Launch system demons: ⓘ

  [loaded] 46 tasks Apple

  [loading] 157 tasks Apple

  [operation] 85 tasks Apple

  Launch officers: ⓘ

  [no charge] com.adobe.AAM.Updater - 1.0.plist (2016-02-26) [Support]

  com.adobe.AdobeCreativeCloud.plist [no charge] (2016-02-26) [Support]

  com.adobe.CS5ServiceManager.plist [no charge] (2011-02-01) [Support]

  [operation] com.bjango.istatlocal.plist (2010-04-23) [Support]

  [loading] com.cisco.anyconnect.gui.plist (2014-06-11) [Support]

  com.kodak.BonjourAgent.plist [no charge] (2012-09-21) [Support]

  com.McAfee.menulet.plist [no charge] (2013-09-30) [Support]

  com.McAfee.reporter.plist [no charge] (2013-09-30) [Support]

  [loading] com.oracle.java.Java - Updater.plist (2014-09-16) [Support]

  [loading] com.oracle.mydesktophelper.plist (2013-08-22) [Support]

  com.Wacom.wacomtablet.plist [no charge] (2013-07-01) [Support]

  Launch demons: ⓘ

  [loading] com.adobe.SwitchBoard.plist (2012-11-16) [Support]

  [operation] com.adobe.adobeupdatedaemon.plist (2016-02-26) [Support]

  [loading] com.adobe.agsservice.plist (2016-02-24) [Support]

  [loading] com.adobe.fpsaud.plist (2016-03-07) [Support]

  [operation] com.cisco.anyconnect.vpnagentd.plist (2014-06-11) [Support]

  [loading] com.malwarebytes.MBAMHelperTool.plist (2016-03-10) [Support]

  [operation] com.mcafee.agent.cma.plist (2014-10-10) [Support]

  com.mcafee.ssm.Eupdate.plist [no charge] (2013-09-27) [Support]

  com.mcafee.ssm.ScanFactory.plist [no charge] (2013-09-27) [Support]

  com.mcafee.ssm.ScanManager.plist [no charge] (2013-09-27) [Support]

  [operation] com.mcafee.virusscan.fmpd.plist (26-09-2013) [Support]

  [loading] com.microsoft.office.licensing.helper.plist (2010-08-25) [Support]

  [loading] com.oracle.java.Helper - Tool.plist (2014-09-16) [Support]

  [loading] com.oracle.java.JavaUpdateHelper.plist (2014-08-11) [Support]

  [operation] com.oracle.mydesktopservice.plist (2015-09-30) [Support]

  [no charge] com.winzip.WinZip - Mac.plist (2012-01-16) [Support]

  User launch officers: ⓘ

  [no charge] com.adobe.AAM.Updater - 1.0.plist (2014-09-18) [Support]

  [loading] com.adobe.ARM. [...]. plist (2014-11-18) [Support]

  [loading] com.google.keystone.agent.plist (2016-03-03) [Support]

  [operation] com.spotify.webhelper.plist (2016-02-29) [Support]

  [loading] com.valvesoftware.steamclean.plist (2016-02-12) [Support]

  Items in user login: ⓘ

  Application of caffeine (/ Applications/Caffeine.app)

  Other applications: ⓘ

  [ongoing] com.adiumX.adiumX.73952

  [ongoing] com.etresoft.EtreCheck.119392

  [ongoing] com.google.Chrome.37152

  [ongoing] com.lightheadsw.caffeine.31712

  [ongoing] com.mcafee.ssm.Eupdate

  [ongoing] com.mcafee.ssm.ScanManager

  [ongoing] com.mcafee.virusscan.ssm.ScanFactory

  [loading] 421 tasks Apple

  [operation] 192 tasks Apple

  Plug-ins Internet: ⓘ

  DirectorShockwave: 11.6.3r633 (2011-10-28) [Support]

  WacomNetscape: 2.1.0 - 1 - SDK 10.8 (2013-07-01) [Support]

  Default browser: 601 - SDK 10.11 (2016-03-09)

  AdobeExManDetect: AdobeExManDetect 1.1.0.0 - SDK 10.7 (2014-03-25) [Support]

  Flip4Mac WMV Plugin: 2.3.2.6 (2010-02-20) [Support]

  OfficeLiveBrowserPlugin: 12.3.6 (2014-09-18) [Support]

  AdobeAAMDetect: 3.0.0.0 - SDK 10.9 (2016-02-26) [Support]

  AdobePDFViewerNPAPI: 10.1.10 (2014-05-15) [Support]

  FlashPlayer - 10.6: 21.0.0.182 - SDK 10.6 (2016-03-11) [Support]

  Silverlight: 5.1.20125.0 - SDK 10.6 (2016-02-12) [Support]

  QuickTime Plugin: 7.7.3 (2016-03-09)

  Flash Player: 21.0.0.182 - SDK 10.6 (2016-03-11) [Support]

  iPhotoPhotocast: 7.0 (2011-01-20)

  SharePointBrowserPlugin: 14.0.0 (2010-08-25) [Support]

  AdobePDFViewer: 10.1.10 (2014-05-15) [Support]

  WacomTabletPlugin: WacomTabletPlugin 2.1.0.2 (2013-07-01) [Support]

  JavaAppletPlugin: Java 8 update 25 (2016-02-12) check the version of

  User Plug-ins internet: ⓘ

  ZoomUsPlugIn: 3.5.33823.1130 - SDK 10.10 (2016-01-08) [Support]

  Safari extensions: ⓘ

  3rd party preference panes: ⓘ

  Flash Player (2016-03-07) [Support]

  Java (2016-02-12) [Support]

  MacFUSE (2008-12-19) [Support]

  WacomTablet (2016-02-12) [Support]

  Time Machine: ⓘ

  Skip system files: No.

  Mobile backups: OFF

  Automatic backup: NON - automatic backup disabled

  Volumes to back up:

  Macintosh HD: Disc size: 499,05 GB disc used: 103,43 GB

  Destinations:

  Time Machine [Local] backups

  Total size: 499,76 GB

  Total number of backups: 4

  An older backup: 16/02/2016, 12:38

  Last backup: 09 03, 2016, 00:27

  Size of backup drive: adequate

  Backup size GB 499,76 > (disc 103,43 GB X 3)

  Top of page process CPU: ⓘ

  5% WindowServer

  2% fontd

  1% kernel_task

  0% cma

  0% AdobeUpdateDaemon

  Top of page process of memory: ⓘ

  1.28 GB Google Chrome Helper (12)

  1.11 GB kernel_task

  967 MB Adobe Photoshop CS6

  442 MB softwareupdated

  Mds_stores 426 MB

  Virtual memory information: ⓘ

  4.31 GB of free RAM

  12,00 GB used RAM (5.47 GB being cached)

  Used Swap 0 B

  Diagnostic information: ⓘ

  Eruption of /Library/Logs/DiagnosticReports/MyDesktopService_2016-03-14-103101_[redacted].c March 14, 2016, 10:31:01

  / Library/Application Support/Oracle / * / MyDesktopService

  March 14, 2016, 10:30:55 test - passed

  March 14, 2016, eruption of /Library/Logs/DiagnosticReports/MyDesktopService_2016-03-14-101903_[redacted].c 10:19:03

  March 14, 2016, eruption of /Library/Logs/DiagnosticReports/MyDesktopService_2016-03-14-100032_[redacted].c 10:00:32

  GET RID OF MACAFE!

  IT does not work, it does not help it does not *!

  all mac anti-virus is a detriment to the operating system at the moment, read the forums here and see other users having bad experiences with all THE of THEM.

  https://community.McAfee.com/thread/54519?TSTART=0

• My computer is VERY slow after upgrade to El Capitan, and especially after I have downloaded MS Office 2016

  After that I downloaded El Capitan, I was satisfied with the content and the speed for about a week. I did a clean install... After 2 weeks of use, I bought the MS Office 2016 and I think after that, I noticed a significant decrease in performance. I mean, like one where I want to throw my computer out the window about 100 times a day. Takes me 30 minutes to start the computer and perform a simple task like the connection to an account on the internet and missing his shot something. 30 minutes! A task that should take 30 seconds.

  I don't know where is the problem. I have a late 2008 Macbook Alu 2.4 GHz, 8 GB Ram, disk SSD (130 GB of free space) and the rest is the default value. Is there a solution, suggestion? Is it fair that my computer can't take El Capitan even with the plug I have, or are at - it something else?

  Thank you that I advance for any help, I'm desperate with her...

  AB

  look at the following link-

  https://discussions.Apple.com/message/29099604#29099604

• "From" field missing in Mac Mail since upgrading to El Capitan

  After that I updated to El Capitan, I seem to have lost the field 'From' in my Mac Mail.

  This means that I can not choose which account to send emails to.

  Someone knows how to fix this?

  Thanks in advance, Craig

  If you do not have this when you select this option to create a new message?

  

• Windows 8 slow since upgrade to Yosemite and Fusion 7

  Hello

  I was previously running Windows 8 pro in Fusion 6 on the Mavericks. I had the computer virtual configured with 2 processors and 4 GB of RAM. The main applications that I use in Windows are:

  
  

  • Visual Studio 2013
  • SQL Server Express
  • SQL Server Management Studio
  • IIS Express
  • Google Chrome (for test and debug with Dev Tools)

  This configuration has worked completely fine, almost as good as a native Windows PC. I've recently updated to Yosemite and Fusion 7.0.1 and upgrading VMWare Tools.

  
  

  This has caused significant performance with my setup problems. More particularly:

  • The action I perform more is switching between VS2013 and Chrome (alt - tab), it was absolutely perfect and was virtually useful instant switching. Now that the same process can last between 1 and 10 seconds.
  • Chrome opening tools now takes on average about 5 seconds.
  • Doing an update of the DOM in the Chrome dev tools now takes a few seconds.
  • Attempt to inspect a DOM element (via the magnifying glass icon) now takes a few seconds.
  • Even switch between the tabs in Chrome now takes anywhere for 10 seconds, which is simply ridiculous. I never have more than about 5/6 Chrome tabs open at any time.

  
  

  All the these was practically instantaneous in the old configuration.

  All these things combined to me are totally unacceptable. Although they are all only small amounts of time on their own, when they are added together, it leads to huge amounts of frustration and ultimately of loads of useless waste of time.

  I did used to close any unnecessary background applications/services, I increased the CPU to 4 cores and 6 GB RAM. Still no significant improvement.

  To move a configuration which worked incredibly well and then supposedly "redevelopment" and end up with an installation that is considerably longer important are very frustrating. I'm hoping that someone somewhere has encountered something similar and may suggest something that I can do to make my setup get the somewhere near where it was before.

  Thank you very much

  Lee

  Stop your virtual machine and change the mode of your material from 11 to 10 and restart your virtual machine.  Your performance should be back to what you expect.  Merger has MAJOR problems with equipment of level 11.

• Since upgrading my ram installed shows 4 gb but says now only 2.93 GB usable why?

  Since I've upgraded to Windows 7 my ram poster now only 2.93 GB usable of my 4 GB.  Why would it be?  And that would be why my system seems slower since upgrade?  The performance is not as fast it was before Vista.  I am more than a little confused!  Why it does not use the full 4 GB?  Only just noticed this, so if someone wouldn't mind to tell me if there is problem I would be very grateful, I'm sure it was something before the 3 upgrade!

  Hi Linda,.

  There is actually a very technical reason for what you see, but basically it's because you're using a 32-BIT operating system.  If you use a 64-BIT operating system you would not see the problem.

  If you are interested, this post does a good job of explaining it is http://blogs.msdn.com/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx , but basically, it's down to the way that the operating system uses the memory and how it spread what you can and cannot use.

  Long story short, that if you stay with 32 BIT, you're stuck with this...

  Hope this helps,
  Jon

  http://www.insidetheregistry.com

• Since the upgrade to El Capitan, my Mac is VERY slow.

  I just have to upgrade Yosemite El Capitan.  Since the upgrade, my Mac is VERY slow.  Spend a lot of time with the spinning beach ball, and slow to change application.

  Why?  What should do?

  Download and run EtreCheck, created by one of his own assistants here in CSA. It is a diagnostic tool that is very useful for us to find problems. It will also give us additional specifications on your Mac. After his execution after the logfile here. It will never contain any personal information.

• I have a late 2009 iMac. When I tried to upgrade to El Capitan. He said that the CHIP shows the h/d is a failure and can not be updated. I have install an external withEl of h/d Cap but it is very slow. the h/d is USB 3 but the iMac's USB 2. the h/d is on

  I have a late 2009 iMac. When I tried to upgrade to El Capitan. He said that the CHIP shows the h/d is a failure and can not be updated. I have install an external withEl of h/d Cap but it is very slow. the h/d is USB 3 but the iMac's USB 2. the h/d is only 5400 RPM. a 7200 RPM 7 / would accelerate the iMac?

  No, because the limiting factor is the computer is USB 2.0, which is how it connects any external drive apart the external drive. As USB 2.0 is much slower, there is no real advantage to a 7200 RPM drive. What you need is a Firewire enclosure that supports FW800 which is much faster than USB 2.0.