SB850-unlocking fourth core of AMD Athlon II X3 435

[Alvendam]

Hello, I want to ask if it's possible to unlock the fourth core of my Athlon II X3 435. I'm using Gigabyte 880GMA-UD2H motherboard. On the CPU is written:
AMD Athlon II
ADX435WFK32GM
CACAC AC 1006FPMW
9C78443B00187

Which according to CPU-World, means that it's with Deneb base core. I read that you need Advanced Clock Calibration feature to unlock AMD CPUs, but SB850 boards doesn't have this feature. I also read that, unlocking can be done with CPU unlock option in the BIOS, but when I try it, I get only black screen. What I'm doing wrong and is it even possible?

 

[clutchc]

Yes, that MB has the capability to unlock disabled cores, and you are correct that the (XXXXX AC) chip is a Deneb with a dormant core and cache. Unfortunately, not all dormant cores are stable. That may be what you are experiencing. If so, you are stuck with a triple core.

Under "advanced bios features", CPU Unlock should be enabled, Core Control should be set to manual, and then you should SAVE and re-boot to BIOS again. At that point going back to the same section of BIOS as above, there should be 3 more cores available instead of just 2. (The 1st core is always enabled).

 

[Alvendam]

"Under "advanced bios features", CPU Unlock should be enabled, Core Control should be set to manual, and then you should SAVE and re-boot to BIOS again.
So if I get black screen (not even getting to POST image) again, should I increase Vcore voltage to get more stability and how much to increase it? This black screen is only fixed with clearing CMOS directly from the motherboard.

 

[clutchc]

That link you posted is for new builds that won't boot on completed assembly. I'm assuming yours is fine when you don't try to unlock the disabled core.

"but SB850 boards doesn't have this feature."
Any AMD chipset from SB710 & SB750 forward have the capability to unlock cores.

 

[Alvendam]

Sorry, I accidentally posted the link. I'm new to the forum and have no idea how is the system working, but didn't find a way to delete it. Yes my pc is fine when I don't try to unlock the core. A small update-I tried to unlock it once again with Vcore at 1.4V and it didn't work. Again black screen, all diodes and fans working. I'm afraid to go to the maximum voltage, because I'm not sure if my cooler can handle it.

 

[clutchc]

It's not the cooler/CPU to be worried about, so much as the voltage regulation system on the MB. Besides, if boosting the Vcore a bit isn't working, I'm sure that Athlon was one that had its core disabled due to a defect.
I've had several Athlon II and Phenom II processors over the years that fell into the 'unlockable' category. It's about a 50-50 chance from what I've experienced. And I've had better luck by far with Phenom IIs than Athlon IIs.

Unfortunately, finding a decent processor to upgrade an AM3 socket today is pretty much a lost cause unless you buy used. Ebay is full of them, but you take your chances. If you DO decide to give ebay a try, look for sellers with several sales under their belt, high rating, and ones that accept returns. I have bought and sold a lot on ebay with no complaints. I still have a 100% rating. Unfortunately I have no AM3 CPUs to sell right now.

 

[Alvendam]

Thank you for the help I'm don't have plans to upgrade my PC in the near future, but if I do, I will certainly search in eBay. All of my parts are got from there and they have no problems. Of course rating and previous sales are critical for choosing seller. Anyway the CPU is doing great job as triple core and I needed unlock just to make my work a bit smoother. Once again-thank you very much! How to give you the "Best answer" thing?

 

[clutchc]

There should be a "select as best answer" link to click on in the replies. If not, don't worry about it.