Phenom X3 720BE: Unlocking 4th core recommendations.

Hello again,

First I would like to thank the community for all the help that has been given! It's much appreciated.

I have recently just finished finding a stable overclock for my CPU. This was my first time overclocking a CPU; the process was not as bad as I expected. After researching I went into the BIOS and changed the multiplier to 17x from 14x. I also added .075v to 1.4 to the CPU. I have yet to do any extensive testing (10hrs+, I suppose), but I was able to pass the OCCT 1hr scan and run Prime95 for over 45 minutes. This seems to be working great, but I would like to learn how to change the memory values in the BIOS. The CPU temp idles at 40C and hits +60-70C.

After I found this setup, I tried to unlock my 4th core. Assuming this is relevant information, my motherboard is a GIGABYTE GA-MA790X-UD4P AM3/AM2+/AM2 AMD 790X and i'm using G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500). As mentioned, I went into the Advanced Clock Calibration and changed the setting to Hybrid/Per Core, restarted, and booted it back up. Windows 7(64-bit) started smoothly--maybe even noticeably faster--and indeed, the fourth core was displayed in my task manager processor tab.

I tried testing the system with both Prime95 and OCCT; both concluding with the same results. After 10-15 minutes my computer would shut down, which was very disappointed to see walking into the room...

While I was monitoring the test I tried to use CPUID to read the temps of my CPU. This program had just worked before I unlocked the cores, but the cores were all displaying 0C, and I am unsure what the TMPIN0-2 correspond to (somewhere in the CPU?). With this problem I was unable to monitor my CPU temp, but I went along with the testing anyway. One thing I did look at was whether all cores were running at 100%. All four were stable for 10 minutes, but then the system crashed.

This is where my main question is, but the ones I have posed above are still problems I am having. I want to know if this error means I need to add more voltage in order to support that core? If I do, how can I read the temperature of my CPU so I know i'm not overheating. Considering I have found a good overlcock for the 3-core setup, should I just keep the 4th core disabled and be happy? What are the benefits of unlocking this, assuming the 4th core in 100% stable--which brings me to my next point.

I read somewhere that I could test a single core with the OCCT software to make sure the 4th core is not a defective one. I tried looking for the option, but I could only find a place to regulate the temperature settings. I must add that the OCCT software also didn't read the CPU temp, that solution didn't work. Can someone recommend a program that can do this?

I have more questions regarding overclocking--which I accomplished on a very basic level--regarding memory and Northgate speeds, but I will save it for another post on a different discussion.

If anyone needs any more information in order to help me with this problem, please let me know!

Thank you.
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  1. ok i can help youw ith some stuff
    1 we have the same exact set up except you have 2 2gb stick while i have 2 1 gb sticks.
    no matter what you do if you unlock the fourth core you will never seen any temp at all. its no wise to unlock it because it causes memory leaks and a bunch of other crapp youd ont wan to deal with. i have jsut succefully unlocked it but it wasnt stable so stopped it was stable a bit at stock 2.8. my voltage is 1.344 . right now i have 3 cores at 3.5 stable
  2. Try using AMD Overdrive to monitor your Temperature. It worked for me.

    I'm using ASRock M3A790GXH/128M w/ American Megatrends Bios V. P1.10. Don't know if it varies with the BIOS.

    For your problem, I think the problem is the Temperature. My 720BE was also able to withstand the Prime95 torture test for 10-15 minutes only. 5 days ago, my computer started producing some loud noise. Followed by a smell of something burning. Then, my computer hanged. I suspect that my processor was overheating. I cooled my computer for two days. Then, I locked the 4th core again and run the Prime95 test. It was constant between 58C to 61C and it last for more then

    So, the conclusion is, I suspect that the stock Heatsink was giving insufficient cooling for the 4th core.

    I'm getting the XIGMATEK Red Scorpion Heatsink this Sunday and will try again with the unlocked 4th core. I'll inform you if something or nothing at all happens.
  3. I've managed to unlock my 4th core but only with 1.5V voltage on stock clock @2.8

    I prefer to use 3 cores with
  4. Hi,

    I have just unlocked the 4th core on my 720BE too and had a similar problem, ie the machine rebooting after around 10mins of Prime95 blend. When running as a tri-core, I had it overclocked to 3.4GHz with 1.400V, stable as a rock for about a year. Then as a quad-core at the same clock speed, I found it just needed a little extra on the vcore to remain stable. I now have the quad-core runnning at 3.4GHz with 1.425V and it has passed Prime95 blend for 6 hours now. I plan to do a longer test at some point soon. From the AMD site, I see that 1.425V is *just* withing the maximum spec for this chip.

    I too have the problem where no software seems to be able to report core temp any longer. CoreTemp, AMD overdrive both report 0C. However, the BIOS still seems able to report the core temp so I think this is just a software issue. At 3.4GHz/1.425V BIOS reports a temperature of ~38C so I'm guessing it will not break the ceiling temp of 73C under load. I do have a decent cooler though, so it might be riskier with the stock cooler. But I agree that guessing is not ideal and would like to find a decent piece of software to monitor the temps.

    BTW, I found the quad-core setup to be stable @ stock 2.8GHz with just 1.375V and from what I've seen, it's very unlikely to overheat at those settings, assuming good general case air flow, reasonable ambient room temps etc, etc
  5. With the 4th core unlocked the stock Heatsink just does a poor job of keeping things cool - My chip was running fine on the stock HS @3.0 GHz. with the 4th core but under Prime95 would reach 69C (which is very close to the 73C shutdown point) so I didn't try anything higher - A couple weeks ago I picked up a TX3 from newegg (on sale for 14.99 and had a $10 off next purchase code so it cost me $4.99) and now the CPU idles at 35C and only reaches 54C under PRime95 @ 3.2Ghz. with all 4 cores - so a better Heatsink is definnitely much better for the system if you are unlocking the extra core !!

    For the temps Everest Ultimate Edition and Gigabyte's Easy Tune 6 will report the CPU temp correctly (the individual core temps show 0C but the CPU temp is correct) and HWmonitor does as well under the tmpin01 (at least that is the one on my system that refers to the CPU temp) Also my X3 720 runs stable at 3.2Ghz. with just 1.312v as well with the 4th core unlocked.

  6. Ya I unlocked my 4th core a couple of days ago, it ran fine at 3.0 ghz reaching 64C after a couple hours on prime95. I just got a Cooler Master Hyper 212+ and it idles 24C and 41C full load. Only the 3 programs above that JDFAN mentioned work and its 8C hotter than it would actually be. I tested this by locking 4th core and I noticed the timpin2(thats what my cpu is with 4th core unlock) showed a temperature 8 degress hotter. This is with a 3.4ghz overclock. I tried getting it up to 3.8ghz but it would BSOD. It wasn't running hot and I have no idea what didn't let it stay stable that high. I'm not too experienced with overclocking but i tried many things with no success after 5 hours.
  7. You can reference a thread i made a week ago about my experience with this chip in regards to unlocking the 4th core and overclocking it to a stable 3.7 (had 3.8 stable with prime95 for 36 hours but i run cpu extensive apps for weeks at a time.) Im using a Coolermaster Hyper 212+ and 7 case fans, in a coolermaster cn900.
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