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RX 480 LN2 overclocking discussion


buildzoid

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Ok so I just did my very first LN2 session with the RX 480. So I figured I'd share my expirience for anyone else intrested as well as start a generally discussion about pushing the RX 480 on cold.

 

Stuff to be aware of

My reference card didn't have either CB or CBB so I ended up running full pot. However I do suspect that my mounting might have failed at some point in time because I was clocking a little low and because I couldn't use the backplate for my Raptor 4 due to it conflicting with my extra cap placements.

 

If you can get into BIOS but not into windows then you need to go into safe mode and reinstall the drivers because Wattman remembers your last unstable OC and is trying to boot with it(praise AMD! /s). If you have an SSD and a clean setup this should not take too long.

 

- Stuff to use to overclock.

As of right now Elmor's LN2 BIOS + GPU Tweak II is the best for voltage control and clocks since it goes to 4Ghz core and 18Ghz mem as well as 2V on the core(not that you will ever reach any of those). At 150% power limit the BIOS gives you a 450W power limit.

 

- Display going black when running benches.

The card has black screen issues. If you push it really low(like say the -178C that I ran at according to my dodgy equipment) with high core voltage you will lose the display. The benchmark is still running you just can't see it. In theory this should be solvable by putting more volts on the .95V rail but I can't figure out how to Vmod it yet. Once I do I will test. To see if the card is running you when blackscreened you need to use a DMM on either Vcore or Vmem as either will show the impact of 3D load. For me mem would hit 1.571V under load and idled at 1.551V.

 

Overclocking

- Core overclocking

I could run windowed 3DM firestrike 1280x1050(IIRC not sure about the resolution) at 1600mhz however my best pass of Firestrike proper was only 1550mhz. Neither more Vcore(tested 1.4-1.6V) nor cold did anything. I suspect I may have just had a bad mount or something which caused these problems. Once I bench again I will know for sure. It is also possible my card just doesn't scale at all.

 

- Memory overclocking

The Samsung memory on my 8GB reference card seems to absolutely hate cold and voltage. I modded my card for 1.72V mem. That didn't help OCing at all. I also tried more VCCI(the voltage in the memory section of Wattman) that also didn't help either and led to the second driver reinstall I did in my session with the card.

The card could pass benches at 9Ghz mem on ambient. With the PCB freezeing through I was fighting for 8.5Ghz so I guess the RAM didn't like the cold either. The 4GB Hynix cards are probably a better choice for pure clock speed on cold IDK about performance someone would need to do a test.

 

BTW here's the memory voltage mod for reference PCB cards(it should be compatible with all card using the GS7256 controller):

http://i.imgur.com/fZz3lPz.png

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Ok so I just noticed something weird. If I try to set over 9Ghz mem in GPU Tweak II with extended OC range it just goes back to 9Ghz. Is there any chance of a fix for this? I was hoping that with more Vmem I could push as much as 10GHz but if the software doesn't allow above 9Ghz I can't really do anything.

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Ok so I just noticed something weird. If I try to set over 9Ghz mem in GPU Tweak II with extended OC range it just goes back to 9Ghz. Is there any chance of a fix for this? I was hoping that with more Vmem I could push as much as 10GHz but if the software doesn't allow above 9Ghz I can't really do anything.

 

It's limited by AMD in the driver.

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  • 3 weeks later...
  • 1 month later...
I have cold slow at 0c :( Powercolor card

 

Try the Elmor LN2 BIOS. It should work on most cards that are close to reference(XFX GTR, Powercolor Red Devil) or reference PCB.

 

I haven't yet started on trying to figure out how the Elmor LN2 BIOS works. Currently busy messing with RAM timings and then getting a full Vmod(Vmem, AUX and 0.95V) guide done for the RX 480 GTR PCB.

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black screen on boot with elmor bios on red devil

 

Good to know I'll see if I can work something out. Does the air BIOS work by any chance? I haven't tried the LN2 BIOS on my GTR yet.

 

BTW the Red Devil has one of the weakest VRMs of the RX 480s so if you bench it on air/water keep the VRM temperature low or it might burn out when doing 1.3V+ approaching or exceeding 1500mhz.

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So I just did some testing and I found something rather odd. The memory voltage setting in Wattman doesn't seem to do anything. I've tested values from 800mv to 1150mv and when checking the various VRMs on my card with a DMM I found that none of the voltages actually changed. So I'm wondering if that voltage setting even does anything. Because after some closer investigation of the PCB I found that the 1V AUX rail is using one of those APW8722 controllers which don't support software voltage control. The IR 3567B seems to only control the core voltage and nothing else.

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  • 2 years later...
On 11/13/2016 at 7:08 AM, buildzoid said:

So I just did some testing and I found something rather odd. The memory voltage setting in Wattman doesn't seem to do anything. I've tested values from 800mv to 1150mv and when checking the various VRMs on my card with a DMM I found that none of the voltages actually changed. So I'm wondering if that voltage setting even does anything. Because after some closer investigation of the PCB I found that the 1V AUX rail is using one of those APW8722 controllers which don't support software voltage control. The IR 3567B seems to only control the core voltage and nothing else.

I know this is old but in my testing I have found that it is just the miniumum voltage that the core needs at maximum memory frequency.  I needed to raise this slightly to stop crashing at low loads like chrome browser when pushing the memory hard.

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  • 8 months later...

For me Elmor BIOS also caused blackscreen. Already had LN2 pot on the GPU at time of flashing :P Didnt backup the original BIOS, so will have to download from second GPU. Do you maybe know which string is related to OTP? Maybe what needs to be done? 

Reference RX480, not aftermarket.

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  • 1 month later...

Yes, it appears like I do. Hooked on the single stage and would be lucky to boost to 900mhz at stock. If I reduced voltage, it would get to 1300 boost, but who wants that. 
 

it’s ok though, I have a beta bios to try for it now. Not the greatest sample around but enough to have fun with. 

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  • Leeghoofd changed the title to RX 480 LN2 overclocking discussion
  • 1 month later...
On 3/4/2020 at 8:28 AM, KaRtA said:

Yes, it appears like I do. Hooked on the single stage and would be lucky to boost to 900mhz at stock. If I reduced voltage, it would get to 1300 boost, but who wants that. 
 

it’s ok though, I have a beta bios to try for it now. Not the greatest sample around but enough to have fun with. 

What RX480 do you have? For the STRIX there's a tool that lets you set the voltage slope, effectively doubling the power limit. On other SKUs you might have to epower.

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