How do i unlock 4th core on Phenom II x3 720?

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We all start out as "noobs" there is absolutely nothing wrong with that. On the contrary, once you start learning and really getting into all the Q&A you aquire more knowledge and eventually the more you know the better you feel. At least that's how I feel. This website by FAR is the best for learning and the peeps I have met are very helpfull, but what really makes me happy is being able to help others and getting that " IT WORKED!! thanks for your feedback" response. In the end its all about helping the person in need and learning new things day-by-day.
 
Thanks again and hopefully someday i can be helpfull to someone too. And just to let you know i set my timings to 4-4-4-15 like you said and jumped to 430Mhz with no errors on memtest. Out-frickin-standing :)
 
I bought it about a month ago here in south australia, so who knows when it was manufactured i will find the box and see if i can find a product or serial number.
 
I do know that it has to do with when the cpu was made. Late February/early March are the only ones that have worked for people. The manufacture date is on the cpu itself, not on the box. I havent looked at mine yet, but i am putting in some new Scythe 120mm fans and redoing my thermal paste next week so i am gonna look then. Did you just set it to Hybrid/Auto to unlock it ?
 


What do you get when you unlock the X2 550's? X3 or X4
Where can we find out more?
 
hey everyone, im about to buy the 720, my board is the gigabyte ga-ma790fx-dq6 got the f7 latest bios, will i be able to unlock 4th core? also will i be able to overclock to over 3ghz? with minimal effort? all i want is to not have my 4890 bottlenecked anymore, i been told this cpu will not bottle it, and if i can get it overclocked by simply altering multiplier, then brilliant! anyone got the same board as me? give me an idea of what i can expect to overclock to? i got a zalman cnps9700 cooler
 
I personally dont think they would create an X3 when they could just sell an X4, you will find MOST X3's are actually X4's with a defective core
 
a x4 priced where the x3 are sold, would cannibalize sales of the x4s. Some times it does make sense, even for a little while, to disable a perfectly healthy 4th core in the name of selling a cheaper chip.
 


and?

thats old news...... the 720be's are pretty awesome when overclocked.... [:jaydeejohn:5]
 
Yesterday I tried to unlock the 4th core of my 720 X3 BE.
After several tries it worked, I saw the X4 20 mentioned in the BIOS, booted up, but system hung on Windows startup screen.
Tried to reboot, but system does not even give POST messages anymore.
Did I fry my Phenom, or what happened here?
If not, do I need to increase voltage first, before unlocking?
 


no.... just lock it back up and use as a Tri-core......

what board and bios do you have?
 
AMD probably has a certain stability test they run on the things, and if they don't pass a certain percentage of the x4s in a tray then they demote them to x3, and repeat the process and if they fail there they go to the x2 bin.

I knew a guy who worked at a CD-ROM maker, and whenever they had more than a certain number in a group fail, they failed the entire group.

Quality assurance on every CPU they make would take forever. So, I imagine they probably take this tact and deem the loss in profits to be less than what they would spend in QAing 100 percent of the product.

I won't complain though. I got an x4 720BE out of it. It runs at 3.4GHz @ ~1.425V (I think). I've heard others getting 3.6, but what do I care? I got a x4 for half the price. 😀 And, hopefully AMD is still making profits :)
 
Well I bought A Phenom 720 and a Gigabyte GA-MA770-UD3 motherboard just last week. I tried overclocking and unlocking the 4th core on Phenom. At first, nothing (using windows 7 64), but i saw that CPU-z showed i have an X4 processor but 4th core didn't run. After a few more tries it froze and i had to clear bios to even get computer to post. Then i tried the same thing with XP 32 and it worked without any problems (just set ACC to firmware 0.82 with bios Fd or to hybrid with Fb). No voltage modification was needed. It ran smoothly for a few days, then i tried the same with vista 32 - it worked the same way as XP 32. Then i tried with vista 64, where the result was the same as in windows 7 64. So, my conclusion was that there may be something wrong with 64 bit channels or whatever on the 4th core. So you can run all 4 cores in 32 bit system but only 3 cores on 64. My decision was 64 bit because it is much faster and you can use more than 3 Gb of memory. Anyway it is a very good processor an rarely you will need 4 cores. Also this motherboard is cheap but full of features. It is very stable, like they say.

I hope someone will have some use of my experience.
 
I read in a local computer magazine about this but it is only avil wiht certain amd phenom X3's i think thet have to have a certain serial number on it does anyone know this serial number??
 
Using a Gigabyte 790GX/SB 750 MB I just unlocked my 720 BE's 4th core, and overclocked it to 3.6Ghz with 1.5V CPU. 8 hour stable running prime 95. Max temp by motherboard sensor (since I can't read the CPU temps anymore) is 48C, based on my temps prior to the unlock, real CPU temp is about 5C higher than that, or 53C with a Vendetta cooler. With just 3 cores I wasn't get overclocks much above 3.7Ghz anyways, so I figure the 4th core for a 100Ghz is probably a decent trade off.
 
Not according to several sources I found, including Tom's.

Quote from: http://www.tomshardware.com/reviews/overclock-phenom-pentium,2366-8.html

Following the same method used for overclocking the Phenom II X2 550, AMD's quad-core Phenom II X4 955 Black Edition was first set to 1.50 volts for the CPU core, 1.65 volts memory, and 1.45 volts for the memory controller.

Quote from http://ixbtlabs.com/articles3/cpu/phenom-2-720-810-overclocking-p1.html

Theoretical overclocking limits of Low-End models with increased voltage are wider than of High-End processors, because their nominal voltage is usually lower, while the recommended maximum is the same (1.55V).

There are a few other websites that support 1.45V-1.55V as max 24/7 voltage for air cooled systems. I'm not trying to be argumentative, if you have other sources that say 1.5V is too high, I'd love to see them!
 


If you read the article you would have seen where it states that they started out with 1.5v and gradually lowered the voltage till they found the "sweet spot".... If you don't believe me that 1.5v is too much juice for 3.6Ghz then I guess you are entitled to your own opinion..... I was just trying to save you from a headache you will encounter in the future 😉




 
On a side note : Not all mobos require the same voltage, some need more some need less. There is no point in using more volts when your CPU does not need them. I could care less what an article suggests, I base my facts on personal experience and trust me I have seen CPU's fry by over-volting when the CPU did not need that much juice... just FYI....
 
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