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

[Chronobodi]

I heard it has to do with the motherboard's BIOs, so, here's mine:


GIGABYTE GA-MA790FXT-UD5P AM3 DDR3 AMD 790FX ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128377

How exactly do you do so?

 

[4745454b]

I'm not sure you can. It takes a special bios, and I believe a board from Biostar. Not all boards will allow this.

 

[Chronobodi]

ahhh, that's ok... just wondering if i could.

is there some sort of list of boards said to support the unlocking of 4th core?

 

[Lee-m]

it would also depends on if that 4th core is really defective (hence it will never work), or if it was working, and just disabled to turn it into an X3.

 

[jitpublisher]

If you would have bought a Phenom II 920, I am pretty sure all 4 cores on them work perfectly staight out of the box.

 

[4745454b]

Yeah, but where is the fun in that?

 

[jcknouse]

I can't guarantee anything, however:

From what I remember reading, most Gigabyte and Biostar 790 chipset boards worked in unlocking the 4th core using the ACC feature by setting it to Auto.

But if your disabled core is really defective, it won't do you any good.

As I also understood it, Asus boards would not unlock because their chipset/BIOS stuff was customized.

That's what I remember reading about. I can't verify any board except for the Biostar TA790GX 128M mobo I bought and it worked.

However, your results may vary and I can't guarantee anything.

 

[Chronobodi]

hmm, dunno if it's worth it, would my computer boot IF the 4th core was indeed defective? like, as in, the other 3 cores still run with the half-a$$ed core?

 

[MykC]

You need a 790GX chipset and apparently the BioStars are the best for unlocking.

If your computer didn't boot you would just have to clear the CMOS and restore default BIOS.

 

[Summer Leigh Castle]

I think it's more dependent on your CPU. Some people are suggesting that fully functional 4-core phenom IIs were intentionally disabled to meet launch and could explained why initial responses were very positive. I don't know if that's true or not but it would be great if we could collect a comprehensive data base of build dates to find "stable" 4th core batches.

I was one of the lucky ones to get a stable 4-core 720x3. I had all four cores up to 3.4 stable at one point with voltage adjustment but found the increase noise of my CPU fan a little too loud for my taste. Less Noise > Marginal CPU gain.

BTW, I'm using a Asrock 790GX motherboard and it works great.

 

[mountie]

If you would have bought a Phenom II 920, I am pretty sure all 4 cores on them work perfectly staight out of the box.

Is the x4 920 a BE? Or AM3?

 

[Chronobodi]

X4 920 is not BE, and it's AM2+.

The AM3 versions should come out this April, i believe.

 

[falcon386]

It is AM3 but it also suit to AM2

 

[Stingingfork]

I've got a Biostar TA790GX Motherboard and a Phenom 2 X3 720 BE CPU. I had no asperations of trying to get a fourth core from the three core processor but after reading the article on Tom's Hardware concerning their attempts at unlocking the fourth core with limited success I decided to enable the ACC in my bios and instantly after rebooting I came up with what appears to be a stable fourth core. I ran Cinebench for establishing a bench mark between the two cores (three and four) and here are the results:

Three Cores:
Rendering (Single CPU): 3226 CB-CPU
Rendering (Multiple CPU): 8582 CB-CPU

Four Cores:
Rendering (Single CPU): 3177 CB-CPU
Rendering (Multiple CPU): 11533 CB-CPU

The change appears to be completely stable at this point but could someone suggest some other benchmark tests that would push the limits of the current four cores to check on it's future stability? I've never been one in the past to run benchmark tests on my new builds. Based on the article I'm not sure if the change from the three to four core processor provides me any added benefits but I'm tempted to leave as four if there isn't any stability problems. What do you think?

 

[jjbtexas]

run prime95

 

[Stingingfork]

run prime95

Thanks jjbtexas for the suggestion. I came across Prime95 (Win 64 bit) this morning and ran it for about 9 hours with the new unlocked CPU passing every test so I guess that puts a dent in the comments I read about the X3's being built from defective X4's.

 

[Chronobodi]

but, why would AMD deliberately disable good functioning cores and sell it as a cheaper 3-core? Don't they make more money in the first place by selling a AM3 Phenom II quad?

 

[Helloworld_98]

they don't, all of them are slightly defective, except one batch which was to meet demand.

and don't forget the 720 is in a fairly high demand due to being better and cheaper than the e8400.

 

[Chronobodi]

so, there's this particular batch of good quads that went on to sell as triples? Dunno if mine's one of them...

 

[Helloworld_98]

it was in late february/early march so I doubt you have one

 

[Chronobodi]

lemme see my order date... i ordered mine on March 4th... That counts as early march... but then again it's luck of the draw.

 

[Chronobodi]

You need a 790GX chipset and apparently the BioStars are the best for unlocking.

If your computer didn't boot you would just have to clear the CMOS and restore default BIOS.

how exactly do you clear the CMOS and restore default BIOS?

 

[successful_troll]

I heard it has to do with the motherboard's BIOs, so, here's mine:


GIGABYTE GA-MA790FXT-UD5P AM3 DDR3 AMD 790FX ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128377

How exactly do you do so?

Cheater...

 

[Chronobodi]

Cheater...

???
Cheating at what? was there a point to your post? It does not make any sense!

anybody respond on how to restore CMOS and BIOS in case it was unsuccessful?

 

[Helloworld_98]

on some mobo's there is a cmos restore switch.