Work in progress -will add more later
Yonah on the Aopen i975Xa-YDG
After a painfully slow start Yonah / MODT has finally made it - and actually starting to be fun. This below hopefully should make the transition a bit easier
Helpful things to to get started on the AOpen i975Xa-YDG :
VMods:
Files:
Temp monitoring:
For internal CPU temp diodes:
For Motherboard CPU temp diode:
For Motherboard CPU temp diode:
Careful - difficult / not possible to revert back to earlier BIOS using WINFLASH proggy - you might have to go DOS flash. Consensus seems to be that R1.03C is the best bios so far ( not sure about R1.04 yet )
Clockgens:
The are several things that influence where your FSB wall is:
Heat
Vcore (+VCCA)
Core
While on air the FSB wall can be caused by 2 things - either a really bad CPU or Heat + Vcore limitations. A good CPU should do around 250 FSB on air ( regardless of multi!), and should go further once Vcore is raised and /or better cooling methods are used. Weird thing is that the FSB can be the same with lower multis - yet once you get colder and raise the Vcore you can get a much higher FSB - until you hit the actual FSB wall of your silicone/CPU. Once that wall is reached even more cooling will not help.
One thing that helped me also greatly to get further on FSB limitation is rasing the FSB slowly. I only use the remote control / Aopen Coo program to raise the FSB. The single mhz steps appears to help not to crash.
Also I noticed that having a certain load helps prevent premature lockups. Once you hit a particular FSB wall - running at that particular max for several minutes can help to get again an extra mhz. It can be a slow process - but this can give you extra 1-6 mhz
The motherboards themselves have no input / very little input on the FSB wall. The same CPUs performed within 1FSB for me on different Aopen i975Xa-YDG boards.
NEW info - Steven has found that during VCORE swings ( droop ) whenever the vocre is on the low end - FSB will lock up much earlier and it is helpful to make sure to rasie FSB whenever the Vcore is at the high end!
With some Yonahs I have found that actually running lower Vcore ( in my case around 1.57V) was helping to get the FSB higher as opposed to running the max 1.62V
Known bugs:
- Can't enter Bios with subzero temps
- Using Molex plug prevents board from booting
- Memset can crash when changing CAS latency
- Clockgen randomly bugs out
- Vcore with current vmod has a max of ~ 1.64V
- Coldbug when CPU is colder than ~ -50C coretemps ( not Evap temps ) This bug prevents you from loading into Windows. For this we might still need the Tcore mod - needs to be checked. This "bug" should only be protection feature of a Windows driver
- Switching between different CPUs on the board without clearing BIOS can cause core temperatures to raise significantly ( +15C air )
- PCI Video cards ( Matrox Millenium maybe others ) and AOpen Coo do NOT get along - prolly becuase of video overlay - causes one core to be fully loaded
- I can not set the bios with my max stable FSB - has to be lower by almost 20MHZ FSB
- ECC memory is always enabled by default in BIOS (might have no impact)
* can't update to older bios from 1.03B ( KIWI )
* board has NO Sata raid, only ata ( KIWI )
* Crossfire only works flawless using ATI driver version 6.4 ( according to Tyrou )
* Crossfire works with ATI driver 6.3 when Write Combining is disabled ( CENTRAL )
Protecting the core:
I hate to admit - but I already managed to kill 2 Yonahs by not following what I constantly preach to my buddies - PROTECT THE CORE!!! One broke ( thank god a free sample ) by simply dropping it on the floor - the other ( of course my golden step 8 CPU I paid mightily for...) by installing a EVAP on one side too tight crushing part of the core.
There are several ways to do so - the easiest using several layers of electrical tape to form a shim (prolly around 4-5 layers depending on the height of tape )
Another easy way is to use the IHS of a socket 478 Intel P3 / P4
The Yonahs appear to be even more fragile to me than Dothan - but that could only be my personal experience..
Voltages:
VCore: Would like to get input here from more users before I tell everyone to run 1.62V 24/7 lol
VCCA: Stock: 1.5V Kyosen runs it as high as 2.5V
need to investigate VCCA voltages myself
VDIMM: Fatty D9: 2.3V
On my D9s I run 2.3V max - since we are stuck will a high FSB/MEM ratio for good good ol' fatty D9s there is no need to go wild on the VDIMM - my set could take the clocks easily with what the BIOS allowed it to run... - would love to get some input from user of different types of ram
PCI-E: I keep
AUTO
I have seen no improvement by raising this voltage for FSB / Clocks. Differnt GPUs might benefit from raising this voltage.
NB voltage: I keep
AUTO
I have seen no improvement by raising this voltage for FSB / Clocks.
OS TWEAKS for benchmarking:
I will have to reserve this space for Tweakmeister Gautam's input - or any other Tweakmeisters. But from my experience there might be very few...but a useMPtimer string and hotfix might be helpful for certain things
Other information and thoughts:
-Do not challenge Tyrou into a benchmarking competition
-T2700 should come out soon, which should bring the Yonah benchmarking and overclocking to a whole new level
-Intel CAN touch this!
-Upcoming Merom CPUs are working flawless with Bios R1.03B on this board
- make sure to set the right CAS latency in BIOS
-BIOS R1.03 should be best for superpi because it has SPeeedstep turned off ( not sure about R1.03C ???)
- we desperately need a BIOS that has all BIOS options unlocked!!!
- the AOpen board only has 2 power phases - there is some minor droop - but nothing too bad!
- WHen setting BIOS clocks above ~ 258FSB the bios will show you incorrect CPU clocks during bootup - the actual clocks will be as set in bios
Running under cold
- Bios R1.03 , R1.03B will not allow you to enter Bios once you reach below 0*C CPU temps ( read from the motherboard probe ). No biggie if you set everything proper in positive temps. Everything else will run perfectly fine
- Bios R1.03C is supposed to allow you to enter the BIOS with neg. Temps
- If CPU core temps ( read by CPU internal probes ) are below ~ -40*C - Windows will crash at loadup - I suspect this is a driver that is supposed to protect the core. I am not sure if Bios R1.03C will help here - but I doubt it. I have seen this -40C with several different Intel type CPUs - in case of the Yonah at least we can boot...
- I was able to run ~ -160*C core temps - but I had to SLOWLY lower temps. Actually the system booted even @ -180*C but appeared to get VERY buggy and unstable - @ -190C it crashed
- Core Temp program will only read up to ~ +5*C - this is becuase of how Intel calculates core temps and not because of proggy.
- HWiNFO32 can read negatives CPU temps from the motherboard Winbond W83783S probe - but once the negative temps are hit the reading will go downards from 255C ( like with AMD ...255*C = -0.X *C)
This probe becomes very inaccurate ~ - 30C and stops / gets stuck soon thereafter
- a trick I used with my single stage to get into bios was to turn off system while the single stage keeps running for a couple of minutes to let the board ( Winbond CPU temp sensor) to cool below - 45*C - and with the cold temps you can go into bios.
JUMPER settings:
Can't find the manual ATM - input would be helpful
http://www.xtremesystems.org/forums/...postcount=1709
Running Merom:
-Make sure to run BIOS R1.03B
-Merom needs less Vcore than Yonah ( ~ 1.3V-1.4V)
-Merom does run hotter
-Coretemp proggy will not show correct temps ( need to subtract 100C minus the shown temp )
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