ohGrFreak -
Im using the same Socket Generation Motherboard as you,
(my system - gigabyte GA-K8NE, 3700+, 1GBram, 6800GS)
so i can lay all the facts out for you...
ALL skt 754 boards do NOT support Dual-channel. thats because of the AMD64's Onboard memcontroller on the CPU Core, not the motherboard.
ALL skt 754 boards only officially support 200fsb(pc3200) with 1 Ram stick used(2Banks of ram), and 166fsb(pc2700) with 2 or more Ram sticks used(4Banks of ram).... However Some motherboard Clock 2xDimms back up to 200fsb automatically... and if it doesnt you can do so Manually, However its considered a OC, and resaults may vary if you do so.... Again thats Due to the CPU's Onboard Memcontroller, not the Board.
and if all 3Dimms are used(6banks of ram) then 166fsb is the max no matter what.
Typically its not an issue to Clock 2 Dimms(2x512[4banks) back up to 200fsb, but OCing any higher with 2Dimms on 754 will not have good resaults.
If your using just 1x1GB(2banks), you may beable to clock higher then 200fsb, But the Limitting Factor is still going to be the CPUs Onboard Memcontroller... IF your already using performance ram.
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On my gigabyte board, i had to Update the BIOS to get all the Advanced Memory TIming options avalible... also Win in BIOS hit (ctrl + F1) on some GIgabyte boards, and it will give you More advanced Options.
If you have all the Mem options avalible to you, you Might beable to run your system Stable at those SPeeds *IF your using 1x1GB of ram.... if you are, you can try Lowering the Command Rate to (2T), maybe loosen up your CAS, and up the CPUs Voltage a tad. (No MOre then ~1.65v on A64 core otherwise you could damage it).
That is ofcourse IF your CPU Multiplier is Locked bellow 10x... Otherwise you coudl just set your Ram FSB to Default 200, and set CPu to 10x200 = 2.0Ghz.
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DO Not be so conserned about your clock speed though, It wont make much of a difference AT ALL, especially on a Semperon and Especialy at such a low differential.
Also note, the AMD 64's do not need to be clocked so high to perform well. Different CPUs perform differently, example = a (Intell Core2 Duo e6300 [1.8ghz)... Is probably faster then Intel Prescott 3.6Ghz.
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The easyest thing to do is to just reset your CMOS and get rid of the OC.... since you would need to Rerun Memtest and Prime95, at each setting untill you got it stable..... that is unless you dont mind or care that you may corrupt your files, or potentially randomely crash or currupt your system.
EDIT: o yea to clearify: IF your Ram Memtests error free at Stock speeds.... then its most likely Not your Ram causing the errors at OC speed *IF your already using performance ram. Its probably the Memcontroller causing errors(lowering Command Rate could help with that). *If your using OCZ value ram, it could be Either or the Memcontroller giving you errors.
Also note though - on my own system i found im able to Run at Lower FSB speed(210) but with the same Perfomrance as higher fsb speed(225), by Tightening my timings and running at a the faster Command Rate. Thats with 1x1Gb of course not 2xDimms.
REMEMBER though All in All, OCing a semperon is not Worth the time. the clock speed is not the only thing Limiting a Semperon.