Frequent Stalls/Freezing on Lion Server 10.7.2

Since the Mac Mini server has an i7 quad-core processor with an integrated Intel HD 3000 Graphics GPU that shares the systems overall installed RAM with the CPU, it could very well be that you are experiencing some kind of an issue with one, or both of the memory modules.

Have you changed, and/or upgraded your Mac Mini Server's memory from 4 to 8 GB's (2x4GB), and if so, what type (brand) of memory did you upgrade your Mini with? And if you did indeed upgrade, or have Apple upgrade your Mac Mini to 8GB's total RAM, your available VRAM should have also increased up to 512MB's -- instead of being limited with the stock 384MB's that's available with only 4GB's installed. It's quite possible that since the VRAM used by the GPU is not discreet - but shared with the main CPU - your integrated Intel GPU might be having some difficulties in maintaining a stable access to one, or both of the of the RAM modules - especially so if your Mac Mini is experiencing any kinds of overheating/cooling issues.

Does your Mac Mini's fan(s) kick on during any of your "stallings", and/or "freezes"? Also, where is your Mac Mini situated: i.e: is it in a place where it gets plenty of circulation/ventilation?

If the problems you are experiencing are not memory related, then it is most probably a CPU/GPU hardware issue that should be address ASAP via your 1 year (or 3 years if you purchased AC) warranty by Cupertino.

I've personally upgraded my Mac Mini 2011 Server with 8GB's (2x4GB) of Kingston's Hyper-X PC3 1666MHz memory modules -- running 30% faster than the stock 1333MHz SODIMM modules do. At first my Mini would not boot with these faster 1666MHz chips installed. But then Apple provided an EFI firmware update about a month, or so ago and I have been enjoying faster speeds -- with a Geekbench 64-Bit score of nearly 9800. Another client of mine tried the same Hyper-X upgrade kit and suffered the same kinds of freezing and stalling issues as you've decribed above. He went back to the originally Apple installed 4GB (2x4GB) memory chips and has had zero problems since.

Couple of things to respond to your questions here:

Firstly; do you have a way of monitoring your Mac Mini's internal temperatures via the onboard sensors? If not, here is a link to a nice, and very valuable little app that comprehensively monitors and reports on all of your Mac Mini's internal hardware temperatures and fans speeds and such:

http://www.bresink.com/osx/HardwareMonitor.html.

You can try it out for free, or buy it for around $10 US for more comprehensively detailed reporting abilities of the utilities hardware monitoring features. And from my own personal experiences in using the program for many years now, it is well worth the extra hamilton so that I can fully monitor all of my Mac's internal hardware in real-time - with a basic and essential utility that Apple themselves should have included by default in OS X 10.7 Lion. This program will let you see exactly what the temperatures are in each CPU core, as well as with the GPU (also integrated on the Intel i7 2635QM quad-core processor).

Secondly: Your intial post listed the Mac Mini's systems log recording some kind of a "kernel" event with the following log statistics:

" **** Debug info for apparent hang in Main graphics engine ****. the very next two log entries state: miniserver kernel[0]: ring head = 0x0e600ba0, wrap count = 0x73, and miniserver kernel[0]: ring tail = 0x00000ba0 ring control = 0x00003001 enabled, auto report disabled, not."

After reading up a bit more on the descriptive technical structure of the Mac Mini's Intel i7 2635QM processor, it seems that the CPU, and GPU share the same memory "ring bus" for both of their L3 caching requirements. Here is a more detailed description of the 2635QM's architecture from notebookcheck.net:

"

Der i7-2635QM offers an integrated graphics card ( Intel HD Graphics 3000) which is clearly faster then the older Intel HD Graphics in the Arrandale CPUs. As the new GPU is included in the CPU, it is also manufactured in 32nm and shares the fast level 3 cache with the CPU cores (using a new ring bus). In the 2635QM it is clocked from 650-1200MHz (Turbo Boost).

Furthermore, an improved dual-channel DDR3 memory controller is included on the CPU die that is used by the CPU and GPU part."

Addition information on the Mac Mini's processor here:

http://www.notebookcheck.net/Intel-Core-i7-2635QM-Notebook-Processor.43923.0.htm l

So...short of you having any mechanical hardware and/or software issues with the hard drive, or with any of the other internal hardware components within your Mac Mini Server, it would seem to point to either a problem (defect) with one, if not both of your currently installed memory modules themselves, or..it could very well be a problem (again, a due to a possible hardware defect) with the CPU/GPU itself - precipitating some kind of an on-chip L3 caching and/or latency issue - therefor requiring you to have to start with the process of attaining a warranty repair order/ticket, so that Apple themselves can quickly repair and/or replace the possibly defective onboard Intel CPU/GPU chip itself, and/or whatever other hardware component that might also be involved in causing these kinds of problems that you have described experiencing with your new Mac Mini Server thus far..

Lastly: I would advice you to try the path of least hassle and resistance for you and your time by simply replacing your existing memory chips with another pair of suitable speed amd type SODIMM modules (even if you have to go back to just 4GB's - 2x2GB's) seeing if you can attain any kind of regular, and reliable stability in your everyday working situations and loads, and at the same time -- testing the Mac Mini out with more intensive CPU/GPU tasks to see if you can replicate the kinds of "freezing", and "studdering" issues that you have been intermittently experiencing with the machine up until now. If you do find that you again encounter the same, or similar types of problems after replacing the existing memory chips, then it is almost a certainty that you do indeed have some sort of hardware (mainly CPU) malfunction and you can then take the appropriate warranty corrective measures to ensure that your new Mac Mini server is up and running to it's fullest potential.

Came here via Googling "kernel[0]: stampWait: Overflowed checking for stamp on MAIN ring: called from"

Experiencing the same issue on my 2011 MacBook Air sparodically after upgrading to 10.8.1.

Non-factory RAM isn't a culprit in my case, nor is overheating. :\