ATI 4850/4870 voltmod thread

[qwertyaas]

Completely agree with you there! The 4850 is a ton of fun pushing it to the wall, and it's fairly cheap by itself. Hell, they ran a $150 deal a few weeks ago on it... Talk about a steal.

My temps were in the high 60Cs, low 70Cs at 1.4v. Topped out at 1125 memory on all cards @ 2.2v, didn't want to push it further.

Had to stop playing with them to focus on the 4870 volt mod tests.

I know how you feel. I got mine for $140 brand new. For that price, it's just too hard to beat (and turn down)!

Too bad I'm afraid to hardmod my card (and never done it either) so I will be sticking to BIOS modding

[W1zzard]

preliminary 4870 mods. still need resistor values. both solder spots are on the back of the card

[wesleyclark]

preliminary 4870 mods. still need resistor values. both solder spots are on the back of the card

BEAUTIFUL. But what is the difference between mvddc, and mvddq? I know vddc is for the GPU core.

[W1zzard]

after 3 seconds of google: MVDDQ is the VDDQ or I/O voltage for the memory chips

[Clemmaster]

Why don't you know about resistance values? What are the enterring resistance in the regulation chips?

[keninishna]

Glorious just what I wanted to hear I just gotta figure out why all this flickering in 2d mode when I edit the bios.

[jimmyz]

Why don't you know about resistance values? What are the enterring resistance in the regulation chips?

I was out, I Have PMed the values to him but he was not responding.

VDDC 50 ohm

the mem mods should be 5k each.

[Big.Wayne]

preliminary 4870 mods. still need resistor values. both solder spots are on the back of the card

Hey there, just wanted to say the pictures are great, I'm not sure who does your photoshop work but say thanks to them too because it makes things very clear and easy to understand for hard-mod nOObs like me!

[vengance_01]

Guys I am trying to do the pencil mod. I have my volt meter and I am getting 1.06 on idle and 1.10 on load. I have a VisionTek version. Temps are fine at under 60C and I look semi stable at 700/1100 at these volts. I am using the right points before. I used this same DVM when I had my GTS 8800. Do I need to flash my bios to unlock the extra voltage? Because outside of windows I measure at 1.14
I think.


Edit I was able to flash my bios. with 1.19 volts on load, 740/1100 looks to be stable. Temps are around 65-66C when running Mass Effect. I think I will keep it here. Temps are pretty high and I am almost close to 4870 performance.

[piebaker]

I had my Powercolor 4850 at 750 and 1150 with bios flash with bios vgpu set 1.4 if that stuff works or not. And 3dmark06 15180 in vista with q6600 @ 3.6

I have a TT Duorb installed on my card. Auto tune went to 690 and 1153 completely stable.

Would a volt mod make the 750 stable then?

[jimmyz]

I had my Powercolor 4850 at 750 and 1150 with bios flash with bios vgpu set 1.4 if that stuff works or not. And 3dmark06 15180 in vista with q6600 @ 3.6

I have a TT Duorb installed on my card. Auto tune went to 690 and 1153 completely stable.

Would a volt mod make the 750 stable then?

It should, mine and most others can scale to over 900 with the mod and proper cooling.

[jeanjean15]

Hello .

I have done the pencil with my HD4850 and have now 1.37 volt for the GPU under water ( swiftech waterblock ) .

I flashed the card at 850 Mhz for the GPU but when i use 3dmark2006 , i have got some artefact on the last scene with snow but no freeze .

At 820 mhz GPU , no more artefact .

So , do you think the card need more voltage or is it normal to have some artefact at 850 mhz GPU ?

Did someone notice the same thing ?

[865pe]

after 3 seconds of google: MVDDQ is the VDDQ or I/O voltage for the memory chips

4870 Pencil mod? GPU or Mem

[jimmyz]

Hello .

I have done the pencil with my HD4850 and have now 1.37 volt for the GPU under water ( swiftech waterblock ) .

I flashed the card at 850 Mhz for the GPU but when i use 3dmark2006 , i have got some artefact on the last scene with snow but no freeze .

At 820 mhz GPU , no more artefact .

So , do you think the card need more voltage or is it normal to have some artefact at 850 mhz GPU ?

Did someone notice the same thing ?

It isn't normal since it went away after dropping speed. You may need a touch more voltage for 850, just keep an eye on the temps.

4870 Pencil mod? GPU or Mem

When the volt mods are confirmed properly and working then we can worry about pencil mods. Though I won't be searching for any others will. I feel a pencil mod is never the answer. hard mod only in my house. I like to be sure It is working right.

[jeanjean15]

It isn't normal since it went away after dropping speed. You may need a touch more voltage for 850, just keep an eye on the temps.

Ok , thanks .

The température is ok , only 50° C max . So , effectively i should increase the voltage to solve the problem .

[jimmyz]

Ok , thanks .

The température is ok , only 50° C max . So , effectively i should increase the voltage to solve the problem .

Or just find a speed/ voltage setting you feel good about. that is what it is all about anyway, not everybody will keep their cards at max clocks all the time. also try a tough bench like crysis etc to test 3DMark is not long enough to test for gaming speed. I like to play for an hour or more.

[jeanjean15]

Or just find a speed/ voltage setting you feel good about. that is what it is all about anyway, not everybody will keep their cards at max clocks all the time. also try a tough bench like crysis etc to test 3DMark is not long enough to test for gaming speed. I like to play for an hour or more.

Thank you for the advice but before deciding which speed will be the best compromise for my use , i like to find the maximum speed with 3dmark2006 and 3dmark2003 because these are very good benchs to do this.

[adpr_02]

Just got my water block.

900/1110 clocks for 24/7. LOVE this card. Have yet to try higher...

What is the voltage ppl. are putting though the memory, 'cause at this point, that is what is bottlenecking me. What do you think the max I should put is? I've got heatsinks on it, btw.

[vengance_01]

nice clocks. My memory will not go above 1100. I even upped the voltage from 2.0 to 2.2 and it did not help. Oh well my 725/1100 clocks are find for air cooling during the hot summer weather out here in CA.

[Miwo]

what voltage are you running with 900? 4850s seem to be hitting that around the 1.4-1.49v ballpark. Try pushing the highest you can go while being artifact free, I am curious to know how much of a difference the power circuitry and additional 6pin Power connector makes in ocing the RV770 to its limits on air/water

Furmark seems to be a great stability tester

[adpr_02]

Right now I'm pushing 1.40v core and 1.09v mem. that was just the first voltage I tried and it worked, so I'm thinking I could push the core a bit more without having to raise the voltage. My temps are amazing: 29C idle and 34C load WITH the vmodd and nearly 50% overclock . haha. I'll keep pushing it more later tonite or tomorrow morning.

Edit:
3dmark06 15942marks (16k to be broken VERY soon, obviously. my cpu wasn't oc'd to benching speed)
Vantage 9057 Marks (to be raised, my cpu wasn't oc'd to benching speed) hehe

Again, this is 24/7 ROCK stable, artifact free, etc, etc. I love this card...

[Miwo]

sweet, go for 1GHz! Run Furmark for stability, seems to stress the cards very high compared to 3DMark and ATITool
http://www.ozone3d.net/benchmarks/fur/

1.4v @ 900 is definitely on the low side compared to 4850 overclocks, so maybe the cores are binned after all

[Laykun]

Glorious just what I wanted to hear I just gotta figure out why all this flickering in 2d mode when I edit the bios.

Hi there. I had this same problem and I can help you there. The flickering that happens between 2d and 3d mode is due to changing memory clocks. You'll notice that the 4870 by default has the same 2d and 3d mem clocks. You'll need to modify your bios to have the same 2d mem clocks as 3d mem clocks to fix this issue (worked for me). Just up your 2d mem clocks to your overclocked 3d mem clocks.

[dean0]

for the vgpu mod on the 4870 can i use any ground eg heatsink screws or does it have to be the one pictured?

[jimmyz]

for the vgpu mod on the 4870 can i use any ground eg heatsink screws or does it have to be the one pictured?

Any ground, I use the ones where the PCI-E power plug hook to the board.