My 2010 27" iMac just received a RAM upgrade: I bought a 16 GB RAM kit by Crucial on amazon. The specification meets this iMac model's requirement, and it has nice ratings.

So right now the memory seats are two 2 GB original RAM + two 8 GB Crucial RAM . The system boots perfectly fine, but when I perform heavy duty tasks or run Rember memory test app, it completely crashes. I have attached two photos that show the RAM seats and crash screen.

enter image description here

Do you think there's any problems with the RAM I just bought or the way I installed them? Please let me know what you think?


I did some experientment with the 4 RAM slots and combinations, see below:

Top: Two original 2 GB RAM. Bottom: Two Crucial 8 GB RAM. Result: Can boot into system perfectly fine, crashes when perform heavy duty tasks or run Rember RAM testing.

Top: Two original 2 GB RAM. Bottom: None. Results: Boot perfectly fine, doesn't crash when perform heavy duty task and run Rember RAM testing.

Top: Two Crucial 8 GB RAM.
Bottom: None.
Results: Doesn't boot into system, stuck at the white screen with a gray apple icon (without seeing progress/ loading circle).

Top: None. Bottom: Two Crucial 8 GB RAM.
Results: Doesn't boot into system, stuck at the white screen with a gray apple icon (without seeing progress/ loading circle).

Top: None. Bottom: One crucial 8 GB RAM in either slot.
Results: Can boot into system but crashes when perform heavy duty teask and run Rember RAM testing.

Error messages:

Interval Since Last Panic Report:  5307777 sec
Panics Since Last Report:          6
Anonymous UUID:                    7A5F46F9-D6A1-46E3-8C3E-4FE67745DF0D

Wed Jan 20 00:01:33 2016
Panic(CPU 2): Unresponsive processor, TLB state:1
EAX: 0x21212121, EBX: 0x00000000, ECX: 0x00000000, EDX: 0x02f8eebc
CR2: 0x30813c95, EBP: 0x93bf3b18, ESI: 0x00000001, EDI: 0x02f8eebc
EFL: 0x00000006, EIP: 0x0029a016, CS:  0x00000008, DS:  0x00000010
Backtrace (CPU 2), Frame : Return Address (4 potential args on stack)
0x8ba3ff48 : 0x2b32c3 (0x93bf39f0 0x0 0x8ba3ff78 0x2aa21d) 
0x8ba3ff78 : 0x2ab423 (0x2 0x93bf39f0 0x0 0x0) 
0x8ba3ffd8 : 0x2a1c2e (0x93bf39f0 0x0 0x0 0x0) 
0x93bf3b18 : 0x25841a (0x2f8eebc 0x0 0x8b9d5508 0x2b367e) 
0x93bf3c68 : 0x2abcc7 (0x2f8eebc 0x30813000 0x0 0x1) 
0x93bf3d48 : 0x2a1a78 (0x93bf3d60 0x1 0x93bf3e78 0x2a9961) 
0x93bf3d58 : 0x2a9961 (0xe 0xc880048 0x10 0x1cd10010) 
0x93bf3e78 : 0x227327 (0x21a9e7a8 0x0 0x1d7e13d4 0x226790) 
0x93bf3ef8 : 0x2275c6 (0x21a9e7c4 0x3 0x2c 0x0) 
0x93bf3f68 : 0x2193f4 (0x0 0x0 0x5 0x295cc1) 
0x93bf3fa8 : 0x2aacb4 (0xffffffff 0x1 0x2a18cc 0x1ed38ea4) 
0x93bf3fc8 : 0x2a1976 (0x0 0x1 0x10 0x1ed38ea4) 

BSD process name corresponding to current thread: Google Chrome

Mac OS version:

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: iMac11,3 (Mac-F2238BAE)

System uptime in nanoseconds: 6536474415254
unloaded kexts:
com.apple.driver.AppleUSBUHCI   4.2.0 (addr 0x11c9000, size 0x65536) - last unloaded 86348958505
loaded kexts:
com.avast.AvastFileShield   2.1.0 - last loaded 29904334326
com.avast.PacketForwarder   2.0
org.pqrs.driver.KeyRemap4MacBook    8.4.0
com.vara.driver.VaraAudio   1.0.3
com.apple.filesystems.msdosfs   1.6.3
com.apple.driver.AppleBluetoothMultitouch   54.3
com.apple.driver.IOBluetoothBNEPDriver  2.4.5f3
com.apple.driver.AGPM   100.12.31
com.apple.filesystems.autofs    2.1.0
com.apple.driver.AppleHWSensor  1.9.3d0
com.apple.driver.AppleMikeyHIDDriver    1.2.0
com.apple.driver.AppleHDA   2.0.5f14
com.apple.driver.AppleUpstreamUserClient    3.5.7
com.apple.driver.AppleMCCSControl   1.0.20
com.apple.driver.AppleMikeyDriver   2.0.5f14
com.apple.kext.ATIFramebuffer   6.3.6
com.apple.driver.AudioAUUC  1.57
com.apple.ATIRadeonX3000    6.3.6
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.ACPI_SMC_PlatformPlugin    4.7.0a1
com.apple.driver.AppleLPC   1.5.1
com.apple.driver.AppleBacklight 170.0.46
com.apple.driver.AppleIRController  303.8
com.apple.driver.AppleUSBCardReader 2.6.1
com.apple.BootCache 31.1
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0d1
com.apple.iokit.SCSITaskUserClient  2.6.8
com.apple.iokit.IOAHCIBlockStorage  1.6.4
com.apple.driver.AppleFWOHCI    4.7.3
com.apple.driver.AppleUSBHub    4.2.4
com.apple.iokit.AppleBCM5701Ethernet    3.0.5b8
com.apple.driver.AppleEFINVRAM  1.4.0
com.apple.driver.AppleAHCIPort  2.1.7
com.apple.driver.AppleUSBEHCI   4.2.4
com.apple.driver.AppleACPIButtons   1.3.6
com.apple.driver.AppleRTC   1.3.1
com.apple.driver.AppleHPET  1.5
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.AppleBluetoothHIDKeyboard  141.5
com.apple.driver.AppleHIDKeyboard   141.5
com.apple.driver.IOBluetoothHIDDriver   2.4.5f3
com.apple.driver.AppleMultitouchDriver  207.11
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.driver.AppleSMBusController   1.0.10d0
com.apple.kext.ATI5000Controller    6.3.6
com.apple.kext.ATISupport   6.3.6
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.AppleSMBusPCI  1.0.10d0
com.apple.driver.AppleBacklightExpert   1.0.1
com.apple.iokit.IONDRVSupport   2.2.1
com.apple.iokit.IOGraphicsFamily    2.2.1
com.apple.iokit.IOFireWireIP    2.0.3
com.apple.driver.BroadcomUSBBluetoothHCIController  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.IOSCSIBlockCommandsDevice   2.6.8
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.IOAHCISerialATAPI   1.2.6
com.apple.iokit.IOSCSIArchitectureModelFamily   2.6.8
com.apple.iokit.IOFireWireFamily    4.2.6
com.apple.iokit.IOUSBUserClient 4.2.4
com.apple.iokit.IONetworkingFamily  1.10
com.apple.iokit.IOAHCIFamily    2.0.6
com.apple.iokit.IOUSBFamily 4.2.4
com.apple.driver.AppleEFIRuntime    1.4.0
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 289.1
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
panic(cpu 1 caller 0x28fc2e): "TLB invalidation IPI timeout: " "CPU(s) failed to respond to interrupts, unresponsive CPU bitmap: 0x4, NMIPI acks: orig: 0x0, now: 0x1"@/SourceCache/xnu/xnu-1504.15.3/osfmk/i386/pmap.c:3572
Backtrace (CPU 1), Frame : Return Address (4 potential args on stack)
0x93ce3b28 : 0x21b837 (0x5dd7fc 0x93ce3b5c 0x223ce1 0x0) 
0x93ce3b78 : 0x28fc2e (0x59a47c 0x4 0x0 0x1) 
0x93ce3be8 : 0x29362f (0x1d3e29f8 0x34902000 0x1 0x8b9a6050) 
0x93ce3d78 : 0x255994 (0x1d3e29f8 0x34902000 0x1 0x1feea9) 
0x93ce3de8 : 0x2589af (0xc84615c 0x1d3e29f8 0x34902000 0x1) 
0x93ce3f38 : 0x2ab83c (0x1d3f4520 0x34902000 0x1 0x3) 
0x93ce3fc8 : 0x2a18da (0x1ed39b04 0x0 0x10 0x220fcf84) 

BSD process name corresponding to current thread: Google Chrome
Model: iMac11,3, BootROM IM112.0057.B00, 2 processors, Intel Core i3, 3.2 GHz, 20 GB, SMC 1.59f2
Graphics: ATI Radeon HD 5670, ATI Radeon HD 5670, PCIe, 512 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x8F), Atheros 9280:
Bluetooth: Version 2.4.5f3, 2 service, 19 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: ST31000528AS, 931.51 GB
Serial ATA Device: HL-DT-STDVDRW  GA32N
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfa100000 / 2
USB Device: TransMemory, 0x0930  (Toshiba Corporation), 0x6544, 0xfa140000 / 5
USB Device: BRCM2046 Hub, 0x0a5c  (Broadcom Corp.), 0x4500, 0xfa110000 / 4
USB Device: Bluetooth USB Host Controller, 0x05ac  (Apple Inc.), 0x8215, 0xfa111000 / 6
USB Device: Internal Memory Card Reader, 0x05ac  (Apple Inc.), 0x8403, 0xfa120000 / 3
USB Device: Hub, 0x0424  (SMSC), 0x2514, 0xfd100000 / 2
USB Device: IR Receiver, 0x05ac  (Apple Inc.), 0x8242, 0xfd120000 / 4
USB Device: Built-in iSight, 0x05ac  (Apple Inc.), 0x8502, 0xfd110000 / 3
  • Welcome to Ask Different. It may be helpful to provide any messages that appear before the time of the crash (from the System Log in Console), and any crash reports (also from Console). They may help identify the cause. Jan 20, 2016 at 6:23
  • We also need to know very specifically which iMac model it is, From About this Mac > System Report… Hardware overview, Model Name, Model Identifier & processor speed. iMacs from that period may support more than 16GB RAM, but only very specific models. Also, what OS you're running, as also some provisos apply.
    – Tetsujin
    Jan 20, 2016 at 7:47
  • Hello Netherlinks, I have added the error messages. please see updates
    – Joe
    Jan 20, 2016 at 8:04
  • Hi @Tetsujin I have added the information you asked for in the new image. I looked it up on apple's website, this iMac is identified as a mid 2010 model. Is it running snow leopard
    – Joe
    Jan 20, 2016 at 8:17

3 Answers 3


Thank you for providing the updated information - however, as I suspected, that is one of the few iMacs from that period that cannot take more than 16GB RAM.

I'm struggling to find data on whether it can specifically use 2x 8GB RAM sticks, though your own experiments would seem to say it cannot & that its maximum configuration would be 4x 4GB sticks.

Info source : Everymac - Aluminum iMac Q&A


† Specifically note that the 21.5" models from the Mid-2010 line (iMac11,2) and the entry-level 27-Inch model -- the iMac "Core i3" 3.2 27-Inch (Mid-2010) -- only support 16 GB of RAM whereas all models from the Mid-2011 line -- 21.5" and 27" -- actually support 32 GB of RAM. If you have a 21.5" model (or the entry-level 27-Inch "Core i3" powered Mid-2010 iMac), please be very certain to identify it precisely to avoid potential disappointment when upgrading the RAM. The 21.5" Mid-2010 models use the 2389 EMC number whereas the 21.5" Mid-2011 models use 2428.

As you are still running Snow Leopard - there is a possibility that the 8GB stick might work if you install the 64-bit firmware update [which so far I'm not able to track down, but you should check Apple Menu > Software Update, just in case]

  • 1
    Hey Tetsujin, Thank you so much for helping me and providing this great resource and answer! I will contact the manufacture and see if I'm able to get an exchange for 4GB rams. Somehow I believed that my Imac was able to take 8GB RAM sticks for up to 32GB in total. Apparently I was wrong :( Everymac is such a great resource, thanks again for sharing I hope this thread will help other people too :) Cheers!
    – Joe
    Jan 20, 2016 at 8:47

I'd like to post an update: I have purchased two Corsair 4GB ram sticks. They work perfectly and passed the memory test. It is indeed a memory compatibility issue - My 27" Imac doesn't take 8GB ram sticks!

Thank you all for your help!


Quick follow up if anyone else runs into this.

The mid-2010 iMac i3 processor can’t handle 8GB sticks. It can only do up to 4GB/slot.

Only the i5 & i7 versions of the mid-2010 iMac can handle 8GB sticks.

Upgrading the processor and ram on my 2010, and tried 2 x 8GB (16GB) with the i3 and had the same issues as OP.

With the i7, I can max out at 4 x 8GB (32GB) okay.

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