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Gigabyte GA-MA785GMT help

post #1 of 5
Thread Starter 
I'm pretty new to oc'ing, but I've been following the Ultimate Overclocking Guide trying to methodically max my OC. I'm struggling with my board however, either when trying to isolate/maximise it or in a combined oc. My system:

the aformentioned mobu
Opteron 1381 AM3 cpu (2.5 GHz quad stock)
8 GB Patriot Viper extreme 1600
450 W Nexus PSU
powercolor HD 4850 card

Here's what's happening:
I've got the CPU turned down to 5x, NB and HT to 5x and memory down to 4x, all voltages manual/normal. Working in 10 MHz increments, I can get the system to 290, running mprime for several minutes (prime95 for linux) each of the last 4 increments. 300 causes failure to boot the OS, but everything else (cpu, nb, ht and mem) is still below normal so I start bumping voltages individually. each goes to max and still failures. I try combo-bumps: NB and HT, CPU and NB VID, memory. fail. open up memory timings, NO BIOS.
Reset CMOS, increment up to 295, same result. Reset Cmos again, I can get back to 290, but now its unstable. The board forces be back to 270 to regain the stability I had been seeing much higher.
The NB doesn't have much effect on stability through 2700 MHz, HT doesn't like it above 2300 but I've read that doesn't make much difference anyway so I've been keeping it around 2K +/-150 MHz. Regardless of how I get there, CPU max frequency tops out around 3.2-ish GHz for all day stability, but it likes it better when the CPU multiplier is max'd and the board frequency is 250-260. I've done the same OC whether the voltage was Auto'd or manual/normal (except the CPU, which goes up .15 to 1.35V)
When I first got the CPU, I was just playing around not knowing anything and I got it up to 295 MHz with 3.75 GHz Cpu clock, everything else auto, but it wasn't entirely stable in mprime.

is this normal for gigabyte mobus to kick you many steps back down? Why can't I get above 290? Why don't any voltage changes improve things? I'm really hoping for a reliable 3.5-3.7 GHz clock, since I've read about this processor going past 4.

Any constructive input is VERY appreciated!
mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
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mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
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post #2 of 5
I don't know how you were able to find and run an Opteron for that, but that is pretyt nice
I would half expect bus clock to max out (start becoming unstable) around there as with most 785G boards. How much voltage have you been pumping through the CPU? It should be manually applied (the voltage) and you may need anywhere between 1.4-1.45V to go further.
post #3 of 5
Thread Starter 
Ignore me If I'm telling you something you already know...
There are basically 4 AM3 Opti's: the 265 (dual core, 3.3, 2 generations, L2 cache) and the 138X (quad core, L3 cache): 1381 is 2.5 GHz, 1385 is 2.7 and 1389 is 2.9. All are rated at 75W, but I understand AMD rates opti's not on TDP, but some other way that I don't fully understand, roughly equating to a 95W desktop proc. Interestingly, the 2nd gen 265 has the same specs and model number as the Athlon II 265, but costs $10 less (probably for the missing hs & fan).
Anyhow, I'd read about the 1381 holding the SuperPi record for a while, and at least one person got it past 4 GHz. Probably very arrogant to think I could come in on my first real attempt and get to within 90% of a potentially single instance max.
The thing that gets me is I read in one of the guides on OCN most decent motherboards should be able to get past 300 MHz. I think this board supports 140W cpu's, and while its not top end, I figured it was decent. And 300 MHz is 3.75 GHz, my goal. And it seems odd that once I hit a failure, the board forces me way down past what at one point was successful. None of this "back it down 3-5 MHz". Mine is nearly 10 times that.
I think you are right, though. 3.25 from 2.5 is pretty good. and at 1.35V, too.
mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
  hide details  
Reply
mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
  hide details  
Reply
post #4 of 5
Opterons are rated ACP ("Average consumption of power") as well as TDP ("Thermal design power"); the latter value may have more to do with heat. The former value AMD bases on both heat and amount of power used in the average workload.
That board should support 125W processors, though the VRMs (older Gigabyte 2007-2008 design) are not exactly the safest and best design for overclocking higher TDP processors... members on this board/variants (BKG w/the 785GM-US2H) have noticed that at certain high voltage levels on high TDP processors, the VRMs will actually start to make noise!

3.25 from 2.5 is probably indeed very good esp. at that voltage. 3.75 might require significantly more voltage, but where significantly more voltage comes into place, at high-usage workloads you may begin to experience such issues related to the VRM system
post #5 of 5
Thread Starter 
thanks for the explanation. I probably misunderstood your statement about finding an opteron for that board.
VRM's are something I haven't researched much yet. I don't recall if I mentioned this before but when I first installed the opti, prior to reading really anything of substance on oc'ing I was blindly turning up the system clock, and at one point I did hit 3.75, but the memory was unstable. It only let me boot it that one time, so after dropping the memory clock it didn't boot. I wish I knew what was going on. Probably had "cool and quiet" on so it under clocked my overclock. Just enough of a taste to make me want it.
anyway, thanks for the input. I'm already looking for better boards I could pick up on a budget.
mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
  hide details  
Reply
mainline
(15 items)
 
  
CPUMotherboardGraphicsRAM
Opteron 1381 Gigabyte MA790FXT-UD5P Radion 4850hd Patriot Sector 5 
Hard DriveHard DriveOptical DriveCooling
WD-640AAS caviar black OCZ Agility 3 does it really matter? Scythe Orocchi 
OSMonitorPowerCase
Ubuntu 64bit Samsung 2233 X2 Seagate 850 W Silver Certified Logisys 
  hide details  
Reply
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