P4G8X Vdimm Mod

[Ace-a-rue]

WARNING....DOING THIS MOD VOIDS YOUR M/B AND MEMORY WARRANTIES!!


Thanks to Hipro5 from Xtreme for pointing to the IC chip that controls the Vdimm on this board.  Using a 10K Radio Shack miniature POT (set to 10K, approx.) you can have 2.72 Vdimm with a bios setting of 2.5v; 2.82 Vdimm with a bios setting of 2.6v and 2.92 Vdimm with a bios setting of 2.7v.  You can go higher on the Vdimm if you lower the resistance on the pot.  I didn't want to adjust the pot just in case the SMD grabber became unclipped.  That way in my situation with 2.6v set in the bios the Vdimm would drop from 2.82 back to 2.6v (actually it overvolts).  At least, you have some staying power for Vdimm to hold the FSB w/o a complete freeze of the system.  You could always set 2.7 in the bios and accept about 2.92-2.94v if you are not very concerned with heating up your memory.  Just remember, if you have heat spreaders they will, IMHO, trap more heat than disperse it.


PARTS NEEDED
1.) 22 or 24 gauge multi-strand wire.
2.) SMD Grabber(s).
3.) RADIO SHACK 10K Miniature POT (or equivalent part).
4.) Low Wattage Soldering Iron & Tin.


EXAMPLE OF PARTS
http://home.nc.rr.com/boeing/smd/parts%20needed.jpg


VDIMM SOLDERING AND HOOK UP PROCEDURE
For the Vdimm mod, you will solder your 22 or 24 gauge multi-strand wire to the SMD grabber. The other end of this wire will be soldered to the middle lug of the 10K POT. Depending on what direction you want to turn the pot to decrease resistance (this increases Vdimm) will determine which outer lug you will use to solder the ground wire. It is best to check the resistance first and then set it to the maximum resistance. WARNING, REMEMBER WHICH DIRECTION INCREASES RESISTANCE, IN FACT, DIAGRAM IT ON PAPER SO YOU DON'T FORGET!


Now use that outer lug you just set the resistance to maximum and solder the ground wire to it. On the other end of the ground wire, attach an electrical grommet that allows you to insert a fastener through to ground to the case or motherboard.


To attach the SMD grabber to the IC pin (or leg) 6 (Red SMD), you will push on the SMD plunger head to extend two very tiny claw type copper feet. You just extend it enough to slide the two claw feet around pin 6 and then release the SMD plunger head slowly so it can grasp on to the leg or pin 6. The approach to the pin should be around 45 degree angle. Coming straight down or straight in horizontally will make it harder to grasp.


To measure the Vdimm voltage, you see an orange SMD grabber attached to the appropriate Mosfet leg.  I would keep that SMD connected all the time so when you want to change the Vdimm you can easily attach the DMM to the extended wire.  When not using this line, cover the bare lead with an electrical cap or electrical tape.


SPECIAL NOTE
Turn the pot very slowy and I mean slowly if you want to increase your Vdimm.  Move it in very small increments and then wait 10-15 secs for the voltage increase to register on the DMM.   If you turn it to fast, you could destroy your memory sticks!  Just beware the turning radius of the miniature POT is less than 180 degrees.


LOCATION OF VDIMM IC AND MOSFET FEED TO MEASURE VDIMM
http://home.nc.rr.com/boeing/p4g8x/P...DIMM%20MOD.jpg

[Daniel ~]

Many thanks Ace! Front page stuff!
http://www.aoaforums.com/

I've also copies your post to our FAQ Topic for permeate inclusion in the glory that is AOA ":O}

[Holst]

I would recomend you use a cermet potentiomite as I did here.
8k3a+ Vagp mod.

a 22 turn cermet pot has much higher resolution that what Ace-A-Rue used above. having 22 turns between extremes makes it much easyer to ajust and loads harder to slip and blow up your board.

http://www.aoaforums.com/forum/attac...&postid=105564

[Holst]

In the UK you can buy cermet pots of various sizes cheaply from www.greenweld.co.uk

[Ace-a-rue]

Thanks for the tip Holst.  That will keep the impatient guys out of trouble...

[Ace-a-rue]

Originally posted by Daniel ~
Many thanks Ace! Front page stuff!
http://www.aoaforums.com/

I've also copies your post to our FAQ Topic for permeate inclusion in the glory that is AOA ":O}

Thank you Daniel for the nice compliment.