GIGABYTE Radeon HD 7870 Windforce3 Voltage Mod?

[TsunamiJuan]

yeah if you can mount them over the Square rensas Mosfets, those are gonna be the main source of the heat. You can take aluminum Channel aswell thats small in size, cut it fit in there, it should work quite well as a heatsink. I go back through and V notch it sometimes with a metal saw to add more fin area to em. its a cheap easy way to add some custom cooling to limited areas. Then some thermal tape on the backside to mount em.

 

[N0ble]

Just put the mod back on and card running nice again at OC.

 

[N0ble]

yeah if you can mount them over the Square rensas Mosfets, those are gonna be the main source of the heat. You can take aluminum Channel aswell thats small in size, cut it fit in there, it should work quite well as a heatsink. I go back through and V notch it sometimes with a metal saw to add more fin area to em. its a cheap easy way to add some custom cooling to limited areas. Then some thermal tape on the backside to mount em.

Sweet, i shall do that.

Can you recommend another point on the back of the card where i can check for core voltage?

I am ok to go poking around on the back of the card with multimeter, with it grounded to the PSU? Providing i dont touch two points together on the card it will not short anything out?

 

[Bobnova]

Correct. I'll MSPaint a pic of read points, hang on.

 

[Bobnova]

Ok here you go. Red circles should all be vcore. Do not short them to their neighbors. Not unless you want to test SCP/OCP on VRM bits capable of a few hundred amps anyway.

I put multiple circles around the place I'd test at.

 

[N0ble]

Ok, it reads 1.25 on vmod card, now going to test on non mod card.

Is it possible that i'm forcing extra voltage to something else that should not be getting the extra voltage with what i have done?

 

[Bobnova]

Maybe, yeah.

 

[N0ble]

ok on non mod card. The voltage started off at the default 1.1 and then moved to 1.3 as i adjusted within the software.

So i guess that now confirms that the mod has worked.

Am i ok soldering a wire to that point and using that as vsense and hook up to my board? or would that be an issue due to the current thats going through that point?

It feels like my other card may be less reluctant to OC, i guess i shall find out once i do the mod to it.

 

[N0ble]

The board has Hynix memory that runs at 1.53.

Do you think it should be safe pushing to 1.63 on air?

 

[Bobnova]

You can look up the IC and see what it is rated for. If it doesn't fry from heat it should be ok.

Feel free to use that as a vsense point. Don't connect it to the previous read point though.

 

[N0ble]

Excellent, the memory mod looks simple to do. But attaching to that small cap was a little pain. Not using my clean free flux next time as it nearly burnt the pad off.

Think I will just cut the current vsense as close to the epoxy as possible and then put a dab of resin over exposed wire to insulate and ensure it does not short. Tomorrow I'm going to get my second card vcore modded and solder my sense points for ROG to the recommended point.

By don't connect to the previous read point I assume you mean not to connect both vsense points together? But I am good to connect the new one to ROG?

Again thankyou both very much for your help, I will be back on tomorrow with more info. If this all goes to plan I will write up a little guide.

 

[Bobnova]

Yeah don't connect the points to each other. Feel free to connect to ROG.

 

[TsunamiJuan]

Excellent, the memory mod looks simple to do. But attaching to that small cap was a little pain. Not using my clean free flux next time as it nearly burnt the pad off.

Think I will just cut the current vsense as close to the epoxy as possible and then put a dab of resin over exposed wire to insulate and ensure it does not short. Tomorrow I'm going to get my second card vcore modded and solder my sense points for ROG to the recommended point.

By don't connect to the previous read point I assume you mean not to connect both vsense points together? But I am good to connect the new one to ROG?

Again thankyou both very much for your help, I will be back on tomorrow with more info. If this all goes to plan I will write up a little guide.

if your almost burning the pad off, than your iron is generally getting to hot, with a combination of to much pressure, heats usually the major enemy on this front though.

 

[N0ble]

if your almost burning the pad off, than your iron is generally getting to hot, with a combination of to much pressure, heats usually the major enemy on this front though.

If I don't use the clean free flux I have no issue. It's just when I use that flux, if I don't use it then it's fine.
The solder does have a flux core so I'm hoping that's enough.

The iron is only a 15watt iron.

 

[N0ble]

I have yet to take the card apart for ddr mod.

But when i do, i will be replacing the thermal paste with some IC Diamond 24-Carat Thermal Compound
http://www.overclockers.co.uk/showproduct.php?prodid=TH-001-ID&groupid=701&catid=27&subcat=

And also fitting some heatsinks on my mosfets as suggested.

But looking at the DDR heat transfer pads they do look a little shabby, whats the best stuff to use on these? I'm assuming that i cant use the thermal paste?

 

[Bobnova]

I'd use the pads that are already there, unless they tore significantly.

 

[N0ble]

Ah ok thanks

I'm using a 15w iron. I'm assuming this is suitable for the job I'm doing?

 

[Bobnova]

Should be, yeah.
In a perfect world you have something with temperature control, but you don't need it.

 

[N0ble]

Ok. Just done the other card and waiting for glue to dry before tweaking. For some reason my other card got about 30c hotter than my modded card even at stock, I'm hoping that it's just due to thermal paste not taking correctly.

I have also wired to the new vsense point.

Will report back in an hour or so

 

[N0ble]

Hmmm I'm a little disappointed.
The first card I did happily sits at 1.26v and clocks nicely to a stable 1320mhz core and not go above 72c with burn in.

My second card which is the same model, seems to need more voltage to run even at 1260mhz, but also even at stock setting seems to run 22c hotter on burn in.
Set at 1260 the temp keeps increasing past 95c. Get random lock ups sometimes when going over 85.
I'm hoping that it's just the heat sink not making proper thermal contact.
Once glue has dried I will take apart and apply new paste to see if anything improves.