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Got a Shuttle SZ68R5 the other day and much to my dismay, it was power-limiting the processor down to about 3.7GHz after a few seconds.
Some searching revealed that ohter users had encountred similar problems, and one had unhid some power-limit related bios options in an early (now unavailable 104 and 105) bioses.
Having access to only the more recent 200 series bioses, I had a go at modding the latest 205. Unfortunately, the structure of the bios had changed since the mods for the 104 and 105 were done, so some improvisation was needed.
The first step was to update the oproms to the latest available (mainly for trim in raid0).
For updating oproms, this tool was most useful:
http://www.softpedia.com/get/System/System-Miscellaneous/UEFI-BIOS-Updater.shtml
and a nice writeup on how to do it here:
http://community.futuremark.com/for...g-tool-updates-almost-all-motherboard-devices
Next, closely inspect available options in AMIBCP (version 4.53 was used).
After testing and encountering a few dead ends, three power limit entries were implicated in my problem.
/Advanced/CPU Configuration/IA Core Current Max(1/8 Amp) (hidden, used AMIBCP to set to USER mode)
/Advanced/Frequency & Voltage Configuration/Power Limit 1 Value(1/8 Watt) (limit of 800)
/Advanced/Frequency & Voltage Configuration/Power Limit 2 Value(1/8 Watt) (limit of 1000)
The other two were readily visible and modifiable in the stock 205 bios, but the limits were too low, capping out at 125 watts for short burst turbo power and 100w for sustained turbo levels. Pretty mediocre bumps for a 2500k with a 95W TDP at stock.
To unlock these options, further modification was needed.
I used MMTool Aptio to find the most likely subsection which may contain the limits and extracted+decompressed it. Poking around the files with a hex editor, I found that the "Setup" portion at volume 02:02:00 at index 7E had both of the turbo limit text strings and exactly one match each for int32 representations of the stock limits 1000 and 800 (1/8 amps).
Modifying these instances to 1600 and 1440 for 200w short turbo and 180w long turbo (max values, user can key in whatever they want under that limit. Seemed reasonable based on my rough assessment of the limits of the cpu vrm.) caused MMtool to refuse to reinsert the files, indicating an FFS error. My guess was a checksum was wrong somewhere.
Moving on to UEFITool and extracting the container (mapping via the GUID value assoicated with the "Setup" entry in MMTool), the same data was found and modified, but this time with a few extra bytes hanging around, probably some needed structural stuff.
Extraction, modification, and reinsertion with UEFITool was successful and I opened the bios again in AMIBCP to verify.
Finally, AMIBCP was used to correct some minor annoyances in default settings (eg: esata port not set to hotplug mode by default) as well as unhide a few other settings which someone might like.
After flashing this bios, the core current limit is user-configurable and the ceilings of the two power-throttling limit settings have been raised to more extreme levels.
Now my system will run at full speed until temperatures become a problem in my 90-degree summertime room.
If you have an SZ68R5 and would like to try the bios, flash at your own risk, but it is working for me
https://drive.google.com/file/d/0ByDtNwJukjzpRDd5Z3NvQVlWbTQ/view?usp=sharing
Edit: Do not bother with this if you are on the stock heatsink.
Some searching revealed that ohter users had encountred similar problems, and one had unhid some power-limit related bios options in an early (now unavailable 104 and 105) bioses.
Having access to only the more recent 200 series bioses, I had a go at modding the latest 205. Unfortunately, the structure of the bios had changed since the mods for the 104 and 105 were done, so some improvisation was needed.
The first step was to update the oproms to the latest available (mainly for trim in raid0).
For updating oproms, this tool was most useful:
http://www.softpedia.com/get/System/System-Miscellaneous/UEFI-BIOS-Updater.shtml
and a nice writeup on how to do it here:
http://community.futuremark.com/for...g-tool-updates-almost-all-motherboard-devices
Next, closely inspect available options in AMIBCP (version 4.53 was used).
After testing and encountering a few dead ends, three power limit entries were implicated in my problem.
/Advanced/CPU Configuration/IA Core Current Max(1/8 Amp) (hidden, used AMIBCP to set to USER mode)
/Advanced/Frequency & Voltage Configuration/Power Limit 1 Value(1/8 Watt) (limit of 800)
/Advanced/Frequency & Voltage Configuration/Power Limit 2 Value(1/8 Watt) (limit of 1000)
The other two were readily visible and modifiable in the stock 205 bios, but the limits were too low, capping out at 125 watts for short burst turbo power and 100w for sustained turbo levels. Pretty mediocre bumps for a 2500k with a 95W TDP at stock.
To unlock these options, further modification was needed.
I used MMTool Aptio to find the most likely subsection which may contain the limits and extracted+decompressed it. Poking around the files with a hex editor, I found that the "Setup" portion at volume 02:02:00 at index 7E had both of the turbo limit text strings and exactly one match each for int32 representations of the stock limits 1000 and 800 (1/8 amps).
Modifying these instances to 1600 and 1440 for 200w short turbo and 180w long turbo (max values, user can key in whatever they want under that limit. Seemed reasonable based on my rough assessment of the limits of the cpu vrm.) caused MMtool to refuse to reinsert the files, indicating an FFS error. My guess was a checksum was wrong somewhere.
Moving on to UEFITool and extracting the container (mapping via the GUID value assoicated with the "Setup" entry in MMTool), the same data was found and modified, but this time with a few extra bytes hanging around, probably some needed structural stuff.
Extraction, modification, and reinsertion with UEFITool was successful and I opened the bios again in AMIBCP to verify.
Finally, AMIBCP was used to correct some minor annoyances in default settings (eg: esata port not set to hotplug mode by default) as well as unhide a few other settings which someone might like.
After flashing this bios, the core current limit is user-configurable and the ceilings of the two power-throttling limit settings have been raised to more extreme levels.
Now my system will run at full speed until temperatures become a problem in my 90-degree summertime room.
If you have an SZ68R5 and would like to try the bios, flash at your own risk, but it is working for me
https://drive.google.com/file/d/0ByDtNwJukjzpRDd5Z3NvQVlWbTQ/view?usp=sharing
Edit: Do not bother with this if you are on the stock heatsink.
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