8rda+ VDD mod

I am going to try this mod out this weekend but am unsure of what ohm resistor to use... there are 2 kinds that my local Radio Shack have in stock that I believe some people are using.

The 680ohm and 1k ohm... I know pretty much all boards will see variable results from one another, but I wanted to find out what peoples voltages are with whichever resistor they used so I can better make my decision....

Thanks for the help!!


nYmph

I tried 2 out 1/2watts, 750 and 820. The 750 gave me 1.85 and the 820 gives me 1.80-81. I stayed with the 820.

You are running 11x200 now? Without a vdd mod?? Wow.

I am almost positive the reason why I can run at 200 now is because I sanded the black border around the NB almost completely down to the metal. (I'm not sure if it was or is metal beneath that black coating, but I saw a spot of what looked silver and that was far enough for me)!

Anyway, that NB is just shaped in a way where the heatsink can't possibly make good contact with it. I had to do this 2 times, cuz the first time I sanded a little bit, put everything back together, and it was hit and miss trying to post at 200fsb.. Then I got mad cuz I had to take everything back apart and sanded that thing down until I could faintly make out a spot of metal. I even put extra AS3 on it just to be SURE that this heatsink was gonna make contact! Popped a 40mm fan on top (stock heatsink BTW) and have been able to run windows at 210fsb and stable at 200fsb...

Anyway, sorry to get off topic a bit, but thought i'd mention it cuz maybe someone can improve their performace by doing the same thing...

Thanks for the post... Anyone else? Please list your resistor type and voltage result.


nYmph

http://8rda.com/page2_2.htm

i use that POTs and also smd grabber...

I set the ohm at 700ohm first and I got 1.83v for VDD

huh? is that rare to run 200 mhz wihouth a vdd mod?
i am running 5-2-2-2 200mhz now with no VDD mod on
my 8rda+

12.5 x 200 @ 2.0 vcore

I wouldn't say it's rare I can run @11.5 x 196 with 1.9vcore no vdd mod done. I have passive cooling on my mosfet tho. I haven't tried to push this thing to 200 but 196 for me is great for pc 3000.

i am able to run 210mhz FSB sync with VDD.... but after vdd now I am running 232mhz

can anyone link to the mod?

I used a variable/adjustable pot at 713 ohms and got 1.85v vdd.

Also, I recently hosed my bios and rather than replace it I just got a new 8rda+. The new one does 200fsb whereas the old one did no more than 183fsb. It seems to be just luck of the draw whether your particular board will do 200 out of the box or not. So, I wouldn't say "rare" but definitely not guaranteed.

The mod can be found here and here.

Elusion, 232fsb is awesome! How low/high voltage wise can you go with that pot?

Has anyone used a fixed 680ohm resistor yet?

nYmph

810 ohm resistor (measured about 800 with DMM) yielded me a 1.77-1.79 vdd in BIOS (none of my voltages stay completely stable with this board).

If you check the 8rdafaq link given re vmods, you will see a formula there for determining what your new vdd would be after the mod. It basically = unmodded vdd + (176/Ohm rating of the resistor). In my case 1.55-1.57 before mod + (176/800) = 1.77-1.79. Pretty much spot on.

232mhz fsb w/ 5-2-2-2.0 timing @ 2.9vdmm @ 1.90vdd PC3200 Twinmos w/ Twinmos chip

I ran 10x210 before the vdd mod, and now run at 9.5x221 with the vdd at 1.92v. I think my Corsair PC3200 has hit it's limit. I used a potentiometer like Elusion.

AC Slater said:

I ran 10x210 before the vdd mod, and now run at 9.5x221 with the vdd at 1.92v. I think my Corsair PC3200 has hit it's limit. I used a potentiometer like Elusion.

Click to expand...

I have the same RAM as you do and I was able to run at 10x220 5,3,2,2 after my mod (1.84v) and unfortunatly I was unable to play around any more because my bios got scrambled. I should be getting my new bios chip some time next week and then I can try for a higher FSB.... But I think that 220-224 will be the limit of the RAM as well, because I did try 225FSB and it wouldnt work....



nYmph

Not to come off the subject But I did run my ram outta sync and was able to run memtest, prime but not 3dmark @ 205 so I do think that the nb cooling and vddmod would put me being able to run 205 or 210 with the ream I have.