ATI 4870X2 Full Vgpumod/Vmemmod And Cooler Guide...

[Jor3lBR]

Oh no, I'm no stranger to soldiering. I took 2 years of electronics in school. I've voltmodded computer parts before, but none since 2003 or so. This looks like a cakewalk compared to the k7v dragon plus vcore mod that I did last! I'll wait on the 18w iron to arrive though. My 25w iron is a rubbish RadioShack unit. The iron is coming in the same package as the trimmers anyways.

--Matt

Mind sharing which on you choose? And where did you get the trimmers (if your in USA)?

[mattkosem]

Mind sharing which on you choose? And where did you get the trimmers (if your in USA)?

I ordered from digi-key. I picked up:

Trimmers:
http://search.digikey.com/scripts/Dk...me=490-2905-ND

Iron:
http://search.digikey.com/scripts/Dk...ame=WPS18MP-ND

--Matt

[SNiiPE_DoGG]

just finished my Vmod according to your guide Riska, thanks much for the great pics of the solder points

used 2 50ohm 25turn pots

(click twice for full res )


quick question about it, what should the resistor read on the DMM when the mod is installed? I set mine to 35 ohms befor installation and now the legs of the VR read 3.5 ohms... the full resistance leg only reads 20ohms. its very very odd maybe I just have a ty DMM....

[mattkosem]

just finished my Vmod according to your guide Riska, thanks much for the great pics of the solder points

What clocks are you seeing? And with what cooling?

Does GPU-Z work for voltage monitoring?

--Matt

[SNiiPE_DoGG]

What clocks are you seeing? And with what cooling?

Does GPU-Z work for voltage monitoring?

--Matt

I have not installed the card as I am waiting on a waterblock for it. I hope to reach 950mhz at least

and no GPU-Z does not work for voltage monitoring

[mattkosem]

I have not installed the card as I am waiting on a waterblock for it. I hope to reach 950mhz at least

and no GPU-Z does not work for voltage monitoring

Well, I guess that's not a big deal. I'll probably only set the voltage once. It's not really something that needs to be changed all the time :-)

Nice! What voltage are you shooting for?

--Matt

[Riska]

You have to set the trimmers to max ohm before powering up the card becaus you dont now how much voltage you will put in the card and maybe you will fry your card!
you can forget about 950 at least many people dont even get that kind og speed under Ln2 i have a lucky card and i have testet many cards and only mine clocks that high on water so set your mind on 875+ mhz the you wont be dissapointed my freind

[Jor3lBR]

You have to set the trimmers to max ohm before powering up the card becaus you dont now how much voltage you will put in the card and maybe you will fry your card!
you can forget about 950 at least many people dont even get that kind og speed under Ln2 i have a lucky card and i have testet many cards and only mine clocks that high on water so set your mind on 875+ mhz the you wont be dissapointed my freind

Riska, did you find a pattern on your tests? Radeons from ATI are the best to OC?

Or it has nothing to do with it a 3rd party could achieve same clocks (Sapphire, Palit, Giga etc)

[NightRaven]

riska just to ask what is the default vmem for the card? thanks

[Riska]

It dosent matter what brand they are the same
The default vmem is about 1.6v but it is hard to say as the vmem is raising and falling automatic on theese cards

[mattkosem]

I have not installed the card as I am waiting on a waterblock for it. I hope to reach 950mhz at least

and no GPU-Z does not work for voltage monitoring

Have you installed your card yet? I was going to do my vmod over this past weekend, but my parts were held up by the holiday (way to go UPS :-/). They're on schedule to arrive today, but I may not do it until the weekend.

--Matt

[SNiiPE_DoGG]

Have you installed your card yet? I was going to do my vmod over this past weekend, but my parts were held up by the holiday (way to go UPS :-/). They're on schedule to arrive today, but I may not do it until the weekend.

--Matt

Ha no I haven't installed it yet, I am waiting on some parts I didn't realize I needed from performance-pcs :\

check my worklog (in sig) for updates, i will post final pics and overclocks when I get it all up and running

[mattkosem]

Well, it turns out my loop isn't up to running an e8600@4.55/1.42v and a 4870X2@890/1.41v. I got the mod installed, and the voltage dialed in to ~1.41v on both GPUs. Unfortunately, my CPU temps were skyrocketing and causing my system to BSOD. I couldn't make it through a pass of Vantage with my CPU kept at 4.55. I struggled with attempting to get both GPUs stable at 890mhz with the CPU under linpak, but was only able to get the CPU and GPUs stable under separate load tests. I eventually found a compromise with the CPU at 4.4@1.42v, but would rather have the extra 150mhz on the CPU than the extra GPU clocks. Temps were still over 85C under OCCTPT after 15 minutes at that point. I pulled the mod and put my system back together. It's running just like it was beforehand.

I might throw another rad in my loop and put it back some day, but I'm over extended on cooling capacity for the moment. How disappointing :-/ Hopefully others will have better results! This mod is probably a good one to shoot for if you're running separate loops for GPU and CPU cooling, or if you're loop isn't radiator constricted!

Thanks for the thread Riska. While my luck was not so good overall, the mod worked exactly as you stated!

--Matt

[scottc19]

What kind of VRM temps are you guys getting, I think I need to cool VRM 1 more as its about 10-20C different than VRM2! These are both located relative to where the stock fan was correct? My stock heatsink on this part is cut to just cover this side, but now with both cores loaded at 1.4v all the temps are find except the vrm1, vrm 2 loads about 80 and vrm 1 gets about 105!!!! I know that VRM's can take heat, but this seems like too much! Have you guys found a better way to cool these. All the other chips on my card have heatsinks attached, this is the only part that uses the stock heatsink, because I couldn't find a heatsink to efficiently cover all of the chips. Also have you guys had better luck leaving the fan on, or taking it off to lower vrm temps..... Thanks

[Razrback16]

Truly a good example of how to write a good guide. Nice job.

[jcool]

Nice guide. I take it there is only the hardmod option available if I want to increase my HD4870X2's clock speeds? No raising the VGPU to 1,5V via software like back in the X1900 days?

Trying to judge if it's worth the hassle.. I got my card watercooled and cold all right (usually below 30C core, card loop only), and it can do a 3D06 pass at around 850 Core. DOesn't like memory clocking at all though, even 950 will give artefacts. What'd you recon I could reach with a VGPU mod, 930-950? I mean it already does 850... oh yeah, waht's the stock VGPU on those cards anyway? I haven't modded a GFX card since my 8800 GTS 640 lol.

[scottc19]

Whats the OVP of this card? I haven't gone past 1.4, but I'm wondering if 1.45 or 1.5 would be ok? Has anyone tried this?

[SNiiPE_DoGG]

Whats the OVP of this card? I haven't gone past 1.4, but I'm wondering if 1.45 or 1.5 would be ok? Has anyone tried this?

I've been up to 1.5 but that was by accident....

[n30c0rt3x]

does this mod from RISKA remove the OVP ??? we plan a Session in Vienna in April and i want to do this awesome mod to my booth 4870x2...

via Softmod the OVP kicks in @ 1,38... any Voltages above GPU-Z reads out 1,45 but on the measure points are @ 1,38