Radeon HD 4850 Voltmods

[Folken]

BTW, what resistance is needed to achieve 1.4V? (I mean what's the setting of the variable 100k resistor?)

 

[fishnchips]

hmmm so by increasing the volts you over clock it and there for burn out the card faster... as we all know cards are not ment to last, just like cpu's they will increase heat so therefore we have to get better cooling incoming and outgoing to cool things down...my honest opnion is just get sli and a faster cpu and faster memory saves all the B/S of O/C..
but if ya happy to do it then go for it...

 

[DavyGT]

I'm having trouble with:

1. I've used mechanical and wood #2 pencils, and the lowest I could get it is ~1500Ohms

is there any other way to pencil mod?

Is the first mod on resistor illustrated above required for:

2. How do i check the resistance decrease using the second one?

1. Try a different pencil, like a 2B pencil and make sure it's sharp. My 2B seems to have hit a bottleneck as well, at 1000Ohms.

2. You don't check the resistance for that one, you measure the vGPU voltage.

 

[kohan69]

hmmm so by increasing the volts you over clock it and there for burn out the card faster... as we all know cards are not ment to last, just like cpu's they will increase heat so therefore we have to get better cooling incoming and outgoing to cool things down...my honest opnion is just get sli and a faster cpu and faster memory saves all the B/S of O/C..
but if ya happy to do it then go for it...

You misunderstand.
By doing a voltmod, you increase the maximum voltage of the video card, increasing it's maximum overclock.
Then you accompany it with aftermarket cooling and edit the bios to use less voltage than stock, you are actually increasing it's lifespam more than triple of what it could serve under the stock cooler and settings.

 

[fishnchips]

seams like a lota work just to get xtra bang for your buck in my books. im heading out tomorrow and getting another 4850 for sli and another mobo quad core and faster memory and a bigger p/s then place a server fan on the side case and 2 fans on the inside one at the front to suck in air and one on the back to suck in the warm air out.
im a suckker for mods but not that into modding a video card when i can go sli. so anyway i see where ya comming from if it extends the life spand longer then thats a good thing for the average user who dont have the $$ to upgrade when it hits the market. shit my bank balance is gonna be poor as a homeless man on the street after this i tell ya but with the games pumping out these days im gonna need the xtra oomph. and yes i can do the mod to my card but dont want to void warrenty is all.

 

[Wile E]

seams like a lota work just to get xtra bang for your buck in my books. im heading out tomorrow and getting another 4850 for sli and another mobo quad core and faster memory and a bigger p/s then place a server fan on the side case and 2 fans on the inside one at the front to suck in air and one on the back to suck in the warm air out.
im a suckker for mods but not that into modding a video card when i can go sli. so anyway i see where ya comming from if it extends the life spand longer then thats a good thing for the average user who dont have the $$ to upgrade when it hits the market. shit my bank balance is gonna be poor as a homeless man on the street after this i tell ya but with the games pumping out these days im gonna need the xtra oomph. and yes i can do the mod to my card but dont want to void warrenty is all.

Yes, it can be a lot of work to do a voltmod, but it's a hell of a lot cheaper than buying a second card.

Also, what if you don't have a board with 2 gfx slots, or don't have a board that supports Crossfire (ATI's version of SLI)? You're left with no choice but to buy the best card you can afford, and to make it as fast as you can.

 

[fishnchips]

your right some times things need to be moded in thoes cases.

 

[Steevo]

Hot damn, anyone here have a Sapphire 1GB card info, or do I get to test and tweak myself this time?

 

[Deleted member 24505]

Fishnchips,2x 4850's is crossfire not sli,and you cant do crossfire with a sli board.If you are buying a new board/chip,make sure you get a crossfire one.

 

[fishnchips]

ahh i c. well crossfire is what i will have to use then i guess
brought the other gear thinking i should go the whole hog and get the 4870 double that and then i can use the 42" lcd tv full time now.
i have the K8 sli am2 motherboard as a spare now
so running two id card's i'll do crossfire on that one in future cause i have the 4850 on that already may as well add another one
now i have wi fi im a lil bit happy cause now i can add logo's to my start up screen in bios anyway thanks for clearing that up for me h ave a great weekend

 

[alex8]

Hello!
I'v pencilmodded my ASUS 4850(first pencil mod). I have now 1150 Ohm, 1.325 V and 765 MHz stable. Isn't stable frequency too low for this voltage?
I use Accelero S1, 120mm+92mm fans.
And my card began to emit strange squeezing noise. What's that?
Thanks, sorry for poor English. Really need help with that noise.

 

[Folken]

You mean buzzing noise? The inductors are subject to make noise when overloaded. Можно перепаять катушки на другие, если известны номиналы... Но гарантия тю-тю.

 

[alex8]

The inductors are subject to make noise when overloaded.

Is that normal or dangerous? I plan on using card in 24/7 mode with those settings...
Thanks for the answer.

 

[Folken]

Just make sure they're not overheating. They will not blow up, relax.

 

[alex8]

Just make sure they're not overheating. They will not blow up, relax.

I mean dangerous for inductors themselves, not for my flat... Thanks!

 

[Spekkie]

Hi guys, I think I hit the monday mornig model since my card is maxed out at 775 @ 1.5V (1st pencil mod) while running on full cover water. And if that isn't bad enough my mem is chewing on 2.3V @full load while I didn't do the vmem mod .
Do you guys think I could RMA this one since the card is running without any problems but for how long and the memIO temps are almost twice as high as the core temp at full load...

Or do you guys have any other suggestions?

 

[Folken]

Or do you guys have any other suggestions?

Maybe you should replace the batteries in your multimeter?

 

[fishnchips]

If you aint done any soldeing then just wipe off the pencil marks with isopro and then leave it alone lol.. but as one guy said you need to add an after market cooler to the card, because it will run hotter.

 

[CozaMcCoza]

Any info on the shorter PCB cards? If it helps I've included a couple of pictures to look at. I wouldn't know the first place to start with locating the right connectors to pencil mod my 4850 and would really appreciate some assistance as this seems the most knowledgeable forum for this type of thing from what I've found.

Many thanks,

Coza

PS Please excuse the shocking screw setup on attaching my Swiftech waterblock to the card. I found using the smaller screws to fiddly and couldn't connect it securely with a decent even pressure so used longer ones and some springs and thumb screws.

 

[Brainless]

Hi CozaMcCoza,
I have the same card. I've successfully done pencil-mod on my card, but it's not a good overclocker. Will post some pictures with right places soon.
Without voltmoding, i was unable to get even 20MHz over stock setting (625MHz).
Now I running it at 750/1075, but not all games are stable. Using ATi tray tool for overclocking.
Overclocking through bios is not good option for this card, unless You set all clocks same (for idle and for load). Crapy power supply on this card can't take a big sudden changes in power demands (when card goes from 500MHz-idle to 750MHz-load for example).
I will try capacitor mod, but waiting to receive a couple of good ultra low ESR capacitors for that purpose.
p.s. Sorry for my poor English.

 

[CozaMcCoza]

If you could get some pictures that would be great thanks! I'm new to BIOS modding on the 4850 but will research it thoroughly enough before attempting anything. I'm not too fussed about the idle/full load clocks being the same as I'm always folding on it if not playing games.

I've read in a few places that the shorted revised PCBs are supposed to have better power management but I guess this depends on the layout as I've seen more than one shorter PCB design out there http://www.bit-tech.net/hardware/2008/10/14/palit-xpertvision-radeon-hd-4850-sonic/1

I've been able to get mine to 675/1000 seemingly stable as loaded it for 24 hours stress testing it which was fine. After a few hours of normal computing the display driver crashed so I've dropped it back down to stock for now till I find out more.

Does ATi/vendors release updated BIOS's for cards like they do for motherboards or is it just for modding the GPU BIOS? I haven't seen any which makes me think they don't

Edit extra

My card is the following: http://www.xpertvision.com/main/vgapro.php?id=175 I've noticed that they specify the RAMDACs at 400 MHz. Can this be OC'd or is this something not too relevant with OC'ing?

 

[Brainless]

I've read in a few places that the shorted revised PCBs are supposed to have better power management but I guess this depends on the layout as I've seen more than one shorter PCB design out there http://www.bit-tech.net/hardware/200...d-4850-sonic/1

This is "SONIC" model. It is with 3-phase power supply (much better that 2-phase on your and my cards).

RAMDAC has nothing with overclocking. It is responsible to send video information to your monitor.

And here are the pictures:



http://g.imageshack.us/img241/xv4850c2ee1.jpg/1/
First one is for VGPU, second is for VMEM.
Be very careful when shading this resistors(with yellow border).
I also put small heatsinks over chips with red border. I noticed that when this chips get hotter, voltage also increase and this provoke more load over them( and more heat respectively). Almost fryed my card. VGPU was 1.35V at idle, and after couple of minutes under FurMark, reached over 1.5V.

 

[Gregsm]

I tried the first pecil mod, using some HB2 pencil, to make few strokes on that black thing in the middle. It made no effect. I dont have multimeter, but my temps were usual 48.5 under 98% load. While with core 750mhz I got BSOD after min in COD4. Do I need to flash it for voltage or whats wrong?

 

[Deleted member 24505]

Welcome to tpu

Please dont try to pencil or hard mod your card without a multi meter.People have done so before and killed their cards.

 

[fishnchips]

you can buy multi's at dicksmith NZ-AU or any electronic's shop for 10 bucks set it to volts and ohm's for other checks