I ended up with an Mid 2010 21.5" iMac that I wanted to dust off and give to my kids. They have light needs, but I'd love to start introducing them to messaging and email with family, plus some educational games.
I can't remember all the problems I've had, but over the last few years I replaced the HDD with an SSD and a few days ago I boosted the RAM from 8GB to the max of 16GB. I reset the PRAM/NVRAM and I thought all my problems were fixed. Then today I logged in to pat myself on the back for getting this up and running again and it was exhibiting the same behavior I was trying to solve.
Specifically, it's been logging me out a handful of times before it "sticks" and lets me use the computer. When booting up, the login screen often looks pixelated, and I can see a black/gray grid in certain spots behind the login screen. It also looks like someone has taken a knife across the screen, showing long lines of distortion fragments. I log in, then bam, get logged out shortly after.
Some things I've tried:
- As mentioned, replaced HDD with SSD and maxed RAM to 16GB
- Completely wiped the SSD and reinstalled High Sierra (the max this machine can take. these issues have occurred through at least the last few major OS updates
- Apple Hardware test won't run (probably because I wiped my drive) and Internet Recovery fails too
- Run memory checks
- Repaired Disk Permissions
I found this thread on reddit about finding crash logs, and when I looked, I found many instances of these two types of crashes:
Kernel_2019-01-25-122634_Boys-iMac.gpuRestart Kernel_2019-01-25-122650_Boys-iMac.gpuRestart Kernel_2019-01-25-122700_Boys-iMac.gpuRestart Kernel_2019-01-25-122749_Boys-iMac.gpuRestart and WindowServer_2019-01-25-122534_Boys-iMac.crash WindowServer_2019-01-25-122626_Boys-iMac.crash WindowServer_2019-01-25-122659_Boys-iMac.crash
Looking at the timestamps, they seem to line up with this afternoon's frustrating experience, crashing about every 20 seconds (log in, auto log out, log back in, repeat).
I don't totally know how to read these reports, but here's an example of some of the outputting the Kernel.gpuRestart crash:
Fri Jan 25 10:26:27 2019 Event: GPU Reset Date/Time: Fri Jan 25 10:26:27 2019 Application: WindowServer Path: Tailspin: /Library/Logs/DiagnosticReports/gpuRestart2019-01-25-102627.tailspin GPUSubmission Trace ID: 0 OS Version: Mac OS X Version 10.13.5 (Build 17F77) Graphics Hardware: ATI Radeon HD 5670 Signature: 0 Report Data: GPURestartReportStart ------------------------ Hung Channels: PM4 ------------------------  AccelChannel: PM4 Pending Command from : GLCtx PendingCommandTimestamp: 0x00000de3, TotalDWords: 0x0000025f, GART Offset=0x0000000020b3a780, stamp_idx=0, estamp=0x00000de3 ------------------------  PM4 HWChannel : Enabled, NotIdle LastReadTimestamp : 0x00000de2 NextSubmitTimestamp : 0x00000e26 [PM4, ts:0x00000de3]: No semaphore wait [PM4, ts:0x00000de3]: semaphore signal: 0xffffff8033e8c9c0 HWSemaphore 0xffffff8033e8c9c0 Signal Event: [PM4 channel TS:0x00000de3 lastReadTS:0x00000de2] ------------------------ GPU HangFlags 0x00000006: AsicHangState 0x00000006, AsicResetRequirement 0x00000002 IndividualEngineHang: 0 NonEngineBlockHang : 1 FenceNotRetired : 1 PerEngineReset : 0 FullAsicReset : 1 HangEngineBitmap : 0x00000000 ------------------------ AMDRedwoodGraphicsAccelerator PCIe Device: [1:0:0] State: ENABLED Configuration: deviceBits: 0x002068c0, capabilityBits: 0x30940100 TotalVideoRAMBytes: 0x0000000020000000 (536870912)
And here's an example from the output of the WindowsServer.crash:
Process: WindowServer  Path: /System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer Identifier: WindowServer Version: 600.00 (312.62) Code Type: X86-64 (Native) Parent Process: launchd  Responsible: WindowServer  User ID: 88 Date/Time: 2019-01-25 12:26:58.581 -0800 OS Version: Mac OS X 10.13.5 (17F77) Report Version: 12 Anonymous UUID: C1090F37-DA86-08E5-7F8C-BF0AAE4C2C91 Time Awake Since Boot: 110 seconds System Integrity Protection: enabled Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Application Specific Information: StartTime:2019-01-25 12:26:25 GPU: MetalDevice for accelerator(0x4b0f): 0x7fcf1570f468 (MTLDevice: 0x0) IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/P0P2@1/IOPP/GFX0@0/ATY,Galago@0/ATY_Galago abort() called Application Specific Signatures: Graphics hardware encountered an error and was reset: 0x00000000
I feel like it's obvious that the gpu is at fault here, but I'm a little over my head and thought I'd ask the more experienced and enlightened.
- Do you think it's likely (how likely?) that replacing the gpu will solve these problems?
- If very likely, I figured out how to find the graphics card I need, but I'm wondering if there cheaper alternatives. I don't need anything heavy duty. This won't be a gaming PC. Just messaging, FaceTime, and a platform for my kids to explore.
Thanks so much for all your help!