Memory discrepancy as reported by Activity Monitor

Lately my Mac's been slowing down to the point that YouTube videos skip and I see the rainbow wheel. I opened the activity monitor and noticed a discrepancy between the amount of memory I have physically installed (shown correctly in the 'About This Mac' window to be 4GB) and the 'Total Amount of Physical RAM Available' displayed in the pie chart shown in the Activity Monitor incorrectly at 3GB. I've never looked at this before so I'm not sure if the discrepancy has always been there or if it's new.

Does/did anyone else have this problem?

Is this the source of current slowdown I'm experiencing?

Should I be concerned?

iRick: The discrepancy may or may not always have been there, depending upon which MBP model you have. Check the Model Identifier of your machine as reported in System Profiler > Hardware Overview. If your machine's Model Identifier is 2,1 or 2,2, it can only access 3.0 GB of RAM even if two 2 GB modules are installed. Any MBP with a Model Identifier of 3,1 or higher should be able to use both modules fully.

Post back with your findings.

You're right it's 2,1. That's pretty sneaky on the part of Apple though. Why did they sell me a Mac with more memory than it can use? I don't expect you to know the answer as I'm just ranting but if you do that would be cool.

Anyhow, that answer teh question that it's always been that way then so why the slow down as of late? Any thoughts?

You're right it's 2,1. That's pretty sneaky on the part of Apple though. Why did they sell me a Mac with more memory than it can use? I don't expect you to know the answer as I'm just ranting but if you do that would be cool.

Anyhow, that answer teh question that it's always been that way then so why the slow down as of late? Any thoughts?

Also for the first time in almost 6 years I saw the "You need to restart your computer" message on my screen (see example in image below). When it started up again, is gave me all this info:

---

Interval Since Last Panic Report: 15545907 sec

Panics Since Last Report: 1

Anonymous UUID: 855FD0CA-2FB6-467E-997F-60C2D234FD74

Tue Feb 7 00:10:16 2012

panic(cpu 1 caller 0x28fc2e): "TLB invalidation IPI timeout: " "CPU(s) failed to respond to interrupts, unresponsive CPU bitmap: 0x0, NMIPI acks: orig: 0x0, now: 0x0"@/SourceCache/xnu/xnu-1504.15.3/osfmk/i386/pmap.c:3572

Backtrace (CPU 1), Frame : Return Address (4 potential args on stack)

0x5bceb9d8 : 0x21b837 (0x5dd7fc 0x5bceba0c 0x223ce1 0x0)

0x5bceba28 : 0x28fc2e (0x59a47c 0x0 0x0 0x0)

0x5bceba98 : 0x292e96 (0x6ecb000 0x1575a000 0x0 0x1)

0x5bcebb48 : 0x26fcf0 (0x7c685 0x5 0x5bcebbf8 0x235975)

0x5bcebbb8 : 0x270316 (0xa31a7b4 0x0 0x0 0xf4000)

0x5bcebc18 : 0x2626fb (0xa31a7b4 0x0 0x0 0xf4000)

0x5bcebd08 : 0x283696 (0x82dcb88 0x18cf4000 0x0 0xf4000)

0x5bcebd88 : 0x284847 (0x82dcb88 0x18cf4000 0x0 0xf4000)

0x5bcebdb8 : 0x24eff4 (0x82dcb88 0x18cf4000 0xf4000 0x15b95000)

0x5bcebdf8 : 0x21dbe5 (0xf6c3f90 0xf6c3b98 0x1fbbfc 0x907)

0x5bcebe38 : 0x210a86 (0xf6c3f00 0x0 0xe825260 0xe7e8110)

0x5bcebe98 : 0x216f84 (0xf6c3f00 0x0 0x0 0x0)

0x5bcebf18 : 0x295914 (0x5bcebf44 0x0 0x0 0x0)

0x5bcebfc8 : 0x2a20f8 (0x7b81f80 0x0 0x10 0x7b81f80)

BSD process name corresponding to current thread: Google Chrome He

Mac OS version:

10K549

Kernel version:

Darwin Kernel Version 10.8.0: Tue Jun 7 16:33:36 PDT 2011; root:xnu-1504.15.3~1/RELEASE_I386

System model name: MacBook2,1 (Mac-F4208CAA)

System uptime in nanoseconds: 3140625360944

unloaded kexts:

com.apple.driver.AppleFileSystemDriver 2.0 (addr 0xd18000, size 0x12288) - last unloaded 2568547231817

loaded kexts:

com.noteburner.driver.cdburner 1.0.0d1

com.parallels.kext.prl_vnic 6.0 12090.660720

com.parallels.kext.prl_netbridge 6.0 12090.660720

com.parallels.kext.prl_usb_connect 6.0 12090.660720

com.parallels.kext.prl_hid_hook 6.0 12090.660720

com.parallels.kext.prl_hypervisor 6.0 12090.660720

com.Cycling74.driver.Soundflower 1.5.2

com.pctools.iantivirus.kfs 1.0.1

com.seagate.driver.PowSecLeafDriver_10_5 5.0.1

com.seagate.driver.PowSecDriverCore 5.0.1

com.apple.filesystems.msdosfs 1.6.3 - last loaded 44569347721

com.apple.driver.AppleBluetoothMultitouch 54.3

com.apple.filesystems.autofs 2.1.0

com.apple.driver.IOBluetoothBNEPDriver 2.4.5f3

com.apple.driver.AppleHDA 2.0.5f14

com.apple.driver.AudioAUUC 1.57

com.apple.driver.SMCMotionSensor 3.0.1d2

com.apple.driver.AppleUpstreamUserClient 3.5.7

com.apple.driver.AppleMCCSControl 1.0.20

com.apple.Dont_Steal_Mac_OS_X 7.0.0

com.apple.driver.AudioIPCDriver 1.1.6

com.apple.driver.AirPort.Atheros21 425.14.7

com.apple.driver.AppleIntelMeromProfile 19

com.apple.driver.ACPI_SMC_PlatformPlugin 4.7.0a1

com.apple.driver.AppleLPC 1.5.1

com.apple.driver.AppleBacklight 170.0.46

com.apple.driver.AppleIntelGMA950 6.3.6

com.apple.driver.AppleIntelIntegratedFramebuffer 6.3.6

com.apple.driver.AppleIRController 303.8

com.apple.driver.AppleUSBTrackpad 201.6

com.apple.driver.AppleUSBTCKeyEventDriver 201.6

com.apple.driver.AppleUSBTCKeyboard 201.6

com.apple.iokit.SCSITaskUserClient 2.6.8

com.apple.BootCache 31.1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1

com.apple.driver.AppleHPET 1.5

com.apple.iokit.IOAHCIBlockStorage 1.6.4

com.apple.driver.AppleAHCIPort 2.1.7

com.apple.driver.AppleSmartBatteryManager 160.0.0

com.apple.driver.AppleUSBHub 4.2.4

com.apple.driver.AppleIntelPIIXATA 2.5.1

com.apple.driver.AppleUSBEHCI 4.2.4

com.apple.driver.AppleUSBUHCI 4.2.0

com.apple.iokit.AppleYukon2 3.2.1b1

com.apple.driver.AppleEFINVRAM 1.4.0

com.apple.driver.AppleRTC 1.3.1

com.apple.driver.AppleFWOHCI 4.7.3

com.apple.driver.AppleACPIButtons 1.3.6

com.apple.driver.AppleSMBIOS 1.7

com.apple.driver.AppleACPIEC 1.3.6

com.apple.driver.AppleAPIC 1.4

com.apple.driver.AppleIntelCPUPowerManagementClient 142.6.0

com.apple.security.sandbox 1

com.apple.security.quarantine 0

com.apple.nke.applicationfirewall 2.1.14

com.apple.driver.AppleIntelCPUPowerManagement 142.6.0

com.apple.driver.AppleHIDKeyboard 141.5

com.apple.driver.IOBluetoothHIDDriver 2.4.5f3

com.apple.driver.AppleMultitouchDriver 207.11

com.apple.iokit.IOSCSIParallelFamily 2.1.1

com.apple.driver.DspFuncLib 2.0.5f14

com.apple.driver.AppleProfileReadCounterAction 17

com.apple.driver.AppleProfileTimestampAction 10

com.apple.driver.AppleProfileThreadInfoAction 14

com.apple.driver.AppleProfileRegisterStateAction 10

com.apple.driver.AppleProfileKEventAction 10

com.apple.driver.AppleProfileCallstackAction 20

com.apple.iokit.IOFireWireIP 2.0.3

com.apple.iokit.IOSurface 74.2

com.apple.iokit.IOBluetoothSerialManager 2.4.5f3

com.apple.iokit.IOSerialFamily 10.0.3

com.apple.iokit.IOAudioFamily 1.8.3fc2

com.apple.kext.OSvKernDSPLib 1.3

com.apple.driver.AppleHDAController 2.0.5f14

com.apple.iokit.IOHDAFamily 2.0.5f14

com.apple.iokit.IO80211Family 320.1

com.apple.iokit.AppleProfileFamily 41

com.apple.driver.AppleSMC 3.1.0d5

com.apple.driver.IOPlatformPluginFamily 4.7.0a1

com.apple.driver.AppleBacklightExpert 1.0.1

com.apple.iokit.IONDRVSupport 2.2.1

com.apple.iokit.IOGraphicsFamily 2.2.1

com.apple.driver.CSRUSBBluetoothHCIController 2.4.5f3

com.apple.driver.AppleUSBBluetoothHCIController 2.4.5f3

com.apple.iokit.IOBluetoothFamily 2.4.5f3

com.apple.iokit.IOUSBHIDDriver 4.2.0

com.apple.iokit.IOUSBMassStorageClass 2.6.7

com.apple.driver.AppleUSBMergeNub 4.2.4

com.apple.driver.AppleUSBComposite 3.9.0

com.apple.iokit.IOSCSIMultimediaCommandsDevice 2.6.8

com.apple.iokit.IOBDStorageFamily 1.6

com.apple.iokit.IODVDStorageFamily 1.6

com.apple.iokit.IOCDStorageFamily 1.6.1

com.apple.driver.XsanFilter 402.1

com.apple.iokit.IOFireWireSerialBusProtocolTransport 2.1.0

com.apple.iokit.IOSCSIBlockCommandsDevice 2.6.8

com.apple.iokit.IOFireWireSBP2 4.0.6

com.apple.iokit.IOATAPIProtocolTransport 2.5.1

com.apple.iokit.IOSCSIArchitectureModelFamily 2.6.8

com.apple.iokit.IOAHCIFamily 2.0.6

com.apple.iokit.IOUSBUserClient 4.2.4

com.apple.iokit.IOATAFamily 2.5.1

com.apple.iokit.IOUSBFamily 4.2.4

com.apple.iokit.IONetworkingFamily 1.10

com.apple.driver.AppleEFIRuntime 1.4.0

com.apple.iokit.IOFireWireFamily 4.2.6

com.apple.iokit.IOHIDFamily 1.6.6

com.apple.iokit.IOSMBusFamily 1.1

com.apple.kext.AppleMatch 1.0.0d1

com.apple.security.TMSafetyNet 6

com.apple.driver.DiskImages 289

com.apple.iokit.IOStorageFamily 1.6.3

com.apple.driver.AppleACPIPlatform 1.3.6

com.apple.iokit.IOPCIFamily 2.6.5

com.apple.iokit.IOACPIFamily 1.3.0

Model: MacBook2,1, BootROM MB21.00A5.B07, 2 processors, Intel Core 2 Duo, 2.16 GHz, 4 GB, SMC 1.17f0

Graphics: Intel GMA 950, GMA 950, Built-In, spdisplays_integrated_vram

Memory Module: global_name

AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x87), Atheros 5416: 2.1.14.6

Bluetooth: Version 2.4.5f3, 2 service, 19 devices, 1 incoming serial ports

Network Service: AirPort, AirPort, en1

Serial ATA Device: FUJITSU MJA2320BH G2, 298.09 GB

Parallel ATA Device: HL-DT-ST DVDRW GSA-S10N

SCSI Device: SCSI Target Device @ 0

USB Device: Built-in iSight, 0x05ac (Apple Inc.), 0x8501, 0xfd400000 / 7

USB Device: Hub, 0x0409 (NEC Corporation), 0x005a, 0xfd100000 / 2

USB Device: Hub, 0x0409 (NEC Corporation), 0x005a, 0xfd140000 / 3

USB Device: Mass Storage Device, 0x8564, 0x1000, 0xfd144000 / 6

USB Device: FA GoFlex Desk, 0x0bc2 (Seagate LLC), 0x5071, 0xfd141000 / 5

USB Device: LaCie Hard Drive USB, 0x059f (LaCie), 0x1018, 0xfd120000 / 4

USB Device: Apple Internal Keyboard / Trackpad, 0x05ac (Apple Inc.), 0x021a, 0x1d200000 / 2

USB Device: IR Receiver, 0x05ac (Apple Inc.), 0x8240, 0x5d200000 / 2

USB Device: Bluetooth USB Host Controller, 0x05ac (Apple Inc.), 0x8205, 0x7d100000 / 2

iRick, part of the problem with installed memory vs addressable memory is the architecture of the system...32 bit systems are only able to address 3 GB of memory, while 64 bit systems can address much, much more, virtually unlimited in practicle terms.

Not sure if the 2 series machines are 32 bit architecture but if so that would explain why the machine has 4 GB but can only address 3 GB.

If Apple sold you a Mac with more RAM than it can use (i.e., if you didn't upgrade the RAM yourself at some point), it was probably because the performance of the installed RAM is better when it's installed in matched pairs, even if not all of it can be used. Your machine could have had a 1GB and a 2GB module installed, but it would be a little slower. I'm not sure whether the difference would have been perceptible or not.

As for the cause of your recent slowdown, that could be caused by any number of things: inadequate free space on the hard drive, a hard drive in the early stages of failure, too many applications running at once for your available RAM, a runaway process hogging the CPU, antivirus software bogging everything down, etc., etc. Does the machine run better after a restart? If so, you're probably just trying to run too many apps at once. If not, there may be a hardware problem of some kind, and that could also be related to your kernel panic.

If the KP hasn't been repeated since you restarted the machine, it may have been just a one-time glitch and not symptomatic of anything more serious. I can't comment on your panic log because I don't have any idea how to interpret it.

I recommend running the Apple Hardware Test that you'll find on one of the discs that were originally shipped with your computer. If any errors are reported, post back here with the exact text of the error message.

There is a very good explanation of the addressable memory on the everymac site, middle of this page. The issue is memory overlap with installed memory of 4 GB and Apple's limit of 3 GB to prevent that from occuring.

Good link, Ralph. I read that years ago, but had forgotten where.

The everymac site is really amazing...some really good info if one just digs a little. I usually just go there to see what type memory machines use, but someone has spent a lot of time compiling information.

I mostly rely on MacTracker for specification info, but I also have EveryMac and apple-history.com bookmarked — I just don't visit them very often. All three references are very valuable.