ASRock 939Dual-SATA2 VCore & VDIMM Mod

[W1zzard]

Introduction

The ASRock 939Dual-SATA2 is a great value oriented board for AMD Socket939. It has both a native PCI-E x16 and an AGP 8x slot.
Unfortunately the BIOS is lacking overclocking options.

With an AMD Venice CPU the maximum CPU voltage available is 1.450V, definitely not enough for some serious overclocking.

Settings for memory voltage are even more limited: "Standard" (2.6V) and "High" (2.7V) just doesn't cut it.

Another issue is that with all official BIOSes you will have great trouble overclocking beyond 275 MHz HTT (v1.40 was the latest when this article was written).

OCWorkbench has released two tweaked BIOS files which fix the 275 MHz clock issues.

VCore Mod

ST Microelectronics' L6711 voltage controller can deliver up to 1.550V to the CPU. The output voltage is selected via VID code. For example if the VID code is 00110, the resulting voltage is 1.400V.

The marked solder pads have the "signal" on the left and ground on the right. So if you bridge one of these, the VID code will always be 0, no matter what the CPU sets.

The following table lists all possible VID code combinations.


For this mod we will change the VID4 code to always return '0'. This is done by bridging the VID4 solder pads with a solder blob or conductive paint.



Now, if the BIOS sets a voltage of 1.100V (VID Code 10010), the resulting VID code would be 00010, which is 1.500V.

With the voltmod done, any voltages listed in the table above that have a 1 for VID4 will get a 0.4V bump. The list in the BIOS will be the same, but the actual voltage is different.

So if you set 1.150V in the BIOS the real output voltage will be 1.550V, if you set 1.125V it's 1.525V, 1.100V is 1.500V an so on.

Voltages which already have a 0 for VID4 remain unaffected.

VDimm Mod

Depending on your needs there are several ways to increase the memory voltage.

3.20V

The red solder pad carries about 3.20V. If you bridge this solder pad to the VDIMM solder pad with a wire, you will directly feed the 3.20V into your memory.

3.30V

If you need more voltage, you can route an orange wire (3.3V) from your ATX Power Connector and connect it directly to the solder pad.
This mod is even more useful if you have a PSU with adjustable 3.3V rail, because changing the 3.3V rail will also change your memory voltage. With two memory modules about 3.5A will run through your wire during load, so make sure you do not use a too thin wire.

Variable Voltage

The BIOS setting VDimm controls the transistor "1". If the voltage in the BIOS is set to Normal, the transistor is closed. When set to High, the transistor is open and will drop the voltage seen on Pin 9 of the LM324. The resistance of resistor "2" will determine how big the dropout is.
The smaller the resistance, the higher the dropout, the higher the resulting memory voltage.
What we are going to do now is solder a trimmer to Pin 9 so we create a second dropout which we can manually control. Connect one pin of the variable resistor to Pin 9 and the other pin to Ground (Pin 11 works good, but any ground is fine).
I found a variable resistor of 500 Ohm works best. At 500 Ohm it will increase the memory voltage by 0.25V, this takes the BIOS setting into account.
Resistor at 500 Ohm: BIOS set to Normal results in 2.85V. BIOS set to High results in 2.95V.
The highest memory voltage you can reach with this mod is 3.05V, at 248 Ohm (BIOS Normal) or 316 Ohm (BIOS High).

[Dynamic]

Nobody has an ASRock motherboard here? Come on BlackPlear, we sure do. I haven't attempted neither mods for my board, since i'm quite happy with my results.

Settings:
CPU:270x9 1.45v
RAM: (166) @221mhz 2225-1T w/ 3.4v
CPU-NB:600

[Anarion]

what happen in "VDimm Mod" ! u just show a pic which has a red square!

[W1zzard]

work in progress

[Anarion]

Originally Posted by Dynamic

Nobody has an ASRock motherboard here? Come on BlackPlear, we sure do. I haven't attempted neither mods for my board, since i'm quite happy with my results.

Settings:
CPU:270x9 1.45v
RAM: (166) @221mhz 2225-1T w/ 3.4v
CPU-NB:600

i read some review which state this board is a little bit slow !
btw last time i bought a SiS base MB it kills me so by any chance do u have problrm with cold booting ! problem with optical drives (some disc ain't read well etc, sub channel data & c2 recovery have some prob ) , some slow/malfunc resources & ...

if not pls let me know coz it seem i will buy one of 'em .

2. u said u do notin (mod), for this seeting u mention , ! realy !? & 3rd. can u give me some temp also if have any comment tnx in advance

[W1zzard]

i'm reviewing this board right now and i must say it rocks, but it needs some mods to oc well

[Anarion]

sound great ,
well i hope this mb with mod ,can go far as the pic or close to it.with air though...

[W1zzard]

the best i could get out of my board is 380, but i think it's safe to say that all boards can do over 350 HTT easily.

[Anarion]

so eager to read ur review sooner , also it's very nice if put a pic for "Variable Voltage" mod which show final mod pic. 2.is it, borad, totaly async imean when use pcie or agp , pci is locked well...

[Dynamic]

The board has been working great for me as you can see my results below. I'm not a hardcore overclocker since my budget has been limited. I have no problems with cold boot ever, so starts up just fine everytime. So far i've used Bios 1.20 but couldn't go over 275FSB. Recently i've flashed my board with the Bios 04XX from a German site and it's been working out just great. For once I've noticed that my Burner didn't load up before, but just a reboot fixed the problem. I'm currently using SpeedFan 4.26 and i've compared it with Everest H.E. 2.20 and Sandra SR3, they seem to be on the same line.

IDLE/LOAD
CPU:24c (Cold night) Avg:32c/40c
Chipset:25c (Cold Night) Avg:28-30c/32c
Power Regulators:25c (Cold Night) Avg:29-30c/39-40c <---Because of all the overclocking results, if i go back to stock, it'll stay around Chipset temps. You also have to understand that i modded a 120mm high speed fan on the side panel which is pushing air right into my CPU, RAM, Power Regulators, and OCZ BOOSTER.

Bios:04XX
270x9 1.45v w/Stock HSF
(166) @221MHz DDR441
2225-1T w/3.4v OCZ DDR BOOSTER
CPU-NB:600
C3D GTO @16pp 550/565 w/Zalman VF700-cu

Cat 5.11 CP
3DMark03:13140
3DMark05:6540

[Anarion]

Originally Posted by Dynamic

IDLE/LOAD
CPU:24c (Cold night) Avg:28-30c/40c
Chipset:25c (Cold Night) Avg:28-30c/32c
Power Regulators:25c (Cold Night) Avg:29-30c/39-40c

You also have to understand that i modded a 120mm high speed fan on the side panel which is pushing air right into my CPU, RAM, Power Regulators, and OCZ BOOSTER.

can u give a link for that site ,

ur temps even avg ones are great , they are look like refrence board's temp, for this chip .

as in wizzard review it reach 80 or on other reviews which i read they reach 55 ....so far...

it's very nice of u which describe in detail important things , very tnx

btw that 12cm on 12v mus sound like a vacum cleaner i have no idea about ur stamania but i can't resist such niose constantly .
@last nice scores ... be well to do

[W1zzard]

the 80 degrees were measured using a temp probe which was stuck into the fins of the heatsink. the testing was done at 300 htt.

maybe those guys reaching 55 degrees used the onboard sensors?

[Anarion]

i think ,he state that ; used a "dr.pc" like temp measure system (i have doubt), btw on that review that guy couldn't go further than 227 htt! (also i can't rermember what was that site ,i just google it )

[Bella]

Hello All,
This is my first time posting, please bear w/ me if I am little unfamiliar w/ this forum and all the good discussions and reviews conducted here. I have been using Asrock mobo and over all I am happy w/ it. Never the less I am a bit disappointed @ asrock for lacking the main ingredients for overclocking, mainly vcore and vdimm. I have done the "ED" voltmods (OCWForum) and as you can see in my sig I was able to achieve a decent overclock for my CPU and Ram on this board. I read the review and the voltmods here and I like the way the vdimm mod is accomplished, and is rather easier than "ED's".
This brings me to my question. The trimmer used is a 500 ohm and I couldn’t find it @ radioshack. I could find a 1K trimmer there, and would like to find out if 1K is the highest resistance and if it could give me the 200-1K variables. The Radioshack sale person was kind of green on the subject, and didn’t know the spec. on this trimmer. It has 3 legs. does this mean one leg is for ground and the other 2 are connected to pin 9, in 2 different ways for 2 different settings or are the 2 legs act like a single resistor? another word hot-wire to pin 9 disconnected and connected to a leg and the 2nd leg connected to pin 9, w/ 3rd leg (ground) to ground?
I really appreciate this vdimm mod and would like to be able to change back to it.
Thank you in advance for the help..

[W1zzard]

a 1k trimmer should work fine too, it's just not as precise to set the voltages.

the outer two legs are used to determine which direction you turn to lower resistance.
so if you use the center and the left leg, turning counter clockwise lowers resistance -> increases voltage.
when using the center and right leg it's clockwise for lower resistance.

I suggest after you decide on which two legs you want to use, break off the third so you can't accidentially use it.

[Bella]

Ok tanx W1zzard. I will do it sometimes tomorrow and report here how I am doing.
Is 1k maximum resistance, and turning will reduce it, and to what? do you know the lower end of this 1K resistor?. I tried to google it but no luck yet. The radioshack guy no help at all. If this 1K trimmer wont be as accurate as you say, what if I just solder a 300 ohm resistor and get ~ 3.volt? My TCCD's only need 2.9-2.95v, and the high/low settings in bios should be sufficient. The "ED's" method was a pain in the butt. I kept the resistor just incase. I have to solder it back in-place before doing your voltmod. right?

[bartonsboy]

Is it ok to do the vdim mod with a conductive pen also? Or should I use wire? I want to do the one that gets me 3.20 volts by bridging to the solder pad. Any info would be greatly appreciated.

Thanks in advance..

[W1zzard]

the 300 ohm resistor thing would work fine but a trimmer is better imo ..
the trimmer is 1k max and 0 ohms at the lower end

bartonsboy: i am not convinced the conductive pen will work. if you try make at least sure you have a wide trace. there will be a lot of current flowing thru it, the lower the resistance of the trace itself, the less heat will be dissipated in the trace.
you can think of it like that: if the electrons are all going thru a narrow trace it will get congested and the electrons rub each other producing heat. if there's more space for them to go they do not rub each other and so create less heat

[Bella]

I tried the 1K resistor on an old mobo (picked one of 3.25 v flat resistor), and you are right. one leg will be 0 and the other @ max(3 legs trimmer). when turning, one lowers when the other increases. the max is ~.30v less than original voltage(3.25v) and shows ~2.95v
But after playing w/ it for about 10 minutes, it lost it and no trimming-just showing original voltage. I think this trimmer is poor quality and I am not taking any chance w/ a new. Don’t want it to break on me during usage. I am glad tried it on an obsolete mobo
Am going to find a quality 500 ohm trimmer from a computer electronics store.
will keep you updated.

[zakward]

I recently bought a 939-Dual SATA2 and the vid 0-4 is not there for some reason.I can see everthing around where it should be but it's not there.Am I going blind or did they remove this from the board?

[W1zzard]

could you make a photo of the area?

[zakward]

If I had a camera that could do the job I would.I think I'll have to see if I can borrow one.

[Bella]

Ok, sorry took me this long to report my progress.
I couldn’t find any reliable 500ohm trimmer so I gave up on this method. But what I did was to solder a 100 ohm resistor to # "2" resistor in the picture, and install a switch between the
3.13v plate and vdimm solder point (the 3.13v method) to have 2 different settings.
If I have the switch on I have 3.05v, off will have 2.90v. For some reason I don’t get as much increase as described in the voltmod here and the one by OCW forum. I think every motherboard is different and the voltage of vdimm mod gives different results.
I now am able to overclock my Venice 3000 to 307.8x9=2770mhz. The results are in my sig.

[Swah]

Originally Posted by zakward

I recently bought a 939-Dual SATA2 and the vid 0-4 is not there for some reason.I can see everthing around where it should be but it's not there.Am I going blind or did they remove this from the board?

For those who don't know where the chip is to be found(yes my english is bad, i'm dutch). It is positioned at the center of the edge of the board, where the socket is located. So say, at the center in the edge of the topside from this board near the processor. Don't be searching at the southside, but near the socket!

Hope you guys find it,

Cheers Swah

[Dynamic]

Anarion,
It's not as bad as you think. I remember when i had my P4 with a Spark 7 from Thermaltake hsf on it, NOW THAT WAS LOUD. Not the system i just built, not that bad. I probably need to bring the high setting down to medium on the 120mm fan to sleep though, but while playing games i can't hear jack with my 5.1 surround sound on. So far so good, i haven't tried overclocking higher. I'm happy.