Using a single eVc on a Dual GPU card.

[DR4G00N]

I just bought an HD 5970 and was wondering if it would be possible to use just one eVc to control both VGPU VT1165 controllers by wiring them up in parallel?

 

Or are both controllers already connected in parallel on the PCB?

[elmor]

I'd expect that they're all on the same bus with different addresses. You can check the resistance between for example SDA between the controllers. And if so, connect the eVc and make a device scan and I'll try to adapt the software HD5970.

[DR4G00N]

Ok, I'll post back once I get it.

 

Thanks.

[DR4G00N]

Got it today and wired it up. The connections from both controllers do look to be on the same bus from what I can tell.

 

Here's the Device scan file:

[elmor]

But only one device is found, which indicates the opposite. Is the resistance between SDA/SCL on both controllers 0ohm? Does it work with the Generic VT1165 profile and if so which voltage is changed?

[DR4G00N]

Sorry, a mistake on my part, they do not show 0Ohm but 9.5kOhm so they are indeed not connected.

 

The Generic VT1165 doesn't do anything.

 

I'll connect them with a bit of wire and see if I can get them both to register.

[elmor]

Sorry, a mistake on my part, they do not show 0Ohm but 9.5kOhm so they are indeed not connected.

 

The Generic VT1165 doesn't do anything.

 

I'll connect them with a bit of wire and see if I can get them both to register.

 

I'd connect the eVc there and make sure it doesn't have the same address first (70h). How about the Generic VT1165 (SVID mode) then? One of the PS voltages should be it.

[DR4G00N]

As I was poking around on the card I noticed that the #1 VDDC Controller (Red) was on the same bus as the VDDCI Controller (Blue). So I connected the #2 VDDC Controller (Magenta) to the VDDCI's SCL and SDA connections. Now both VDDC Controllers are registered on the device scan (70,71) and can be controlled just fine using the Generic VT1165 Profile.

 

But the VDDCI doesn't register on the device scan even though all three controllers are connected, which I find is odd since they are all VT1165's.

 

EDIT: Hmm, yeah I don't think this'll work actually. On first boot it worked fine but on the second boot the VDDCI was locked to 1.05V and changing the voltage caused it to crash.

 

I'll try connecting them one at a time and checking the address' now.

 

EDIT #2: Nevermind, I tried it a few more times and it works great, must've been an error of some sort.

Edited September 5, 2016 by DR4G00N

[elmor]

As I was poking around on the card I noticed that the #1 VDDC Controller (Red) was on the same bus as the VDDCI Controller (Blue). So I connected the #2 VDDC Controller (Magenta) to the VDDCI's SCL and SDA connections. Now both VDDC Controllers are registered on the device scan (70,71) and can be controlled just fine using the Generic VT1165 Profile.

 

But the VDDCI doesn't register on the device scan even though all three controllers are connected, which I find is odd since they are all VT1165's.

 

EDIT: Hmm, yeah I don't think this'll work actually. On first boot it worked fine but on the second boot the VDDCI was locked to 1.05V and changing the voltage caused it to crash.

 

I'll try connecting them one at a time and checking the address' now.

 

EDIT #2: Nevermind, I tried it a few more times and it works great, must've been an error of some sort.

 

The situation you have now is most likely that the two VT1165 controlling vcore are at the same address at 0x70 and both manages to accept the i2c command to change voltage. This is quite unreliable for sure, but whatever works I guess 0x71 should be the VDDCI voltage. You can try this version https://www.dropbox.com/s/cpff1olx592apm3/eVc%20v1b5_vt1165t1.zip?dl=0, it has Generic VT1165 (SVID mode) 0x70 and 0x71.

[DR4G00N]

Thanks a lot, that works perfect. Both VDDC & VDDCI are fully adjustable.

[DR4G00N]

I have to update and say that I couldn't get this to really work problem free in the end. It sometimes works and other times it just breaks the card.

I removed it for the time being.

 

Two separate eVc's are the way to go for this card. #1 for VDDC 1 & VDDCI, #2 for VDDC 2.