Modding 4870 Asus Top BIOS with RBE v1.19 - Voltage stays high at idle

[dostov]

Hey guys! dostov here from TRP Forums.

I'm currently trying out RBE v1.19 and the new voltage registers options on a 512MB reference HD4870. I'm trying to build upon the Asus Top BIOS to both increase the 3D voltage and decrease the 2D voltage. Correct me if I'm wrong, but the Asus Top BIOS has locked voltages.

So, what I first did was to enable superior powerplay with RBE to get rid of the locked voltages. Then, I upped the 3D voltage to 1.3250v in register 18. Others values were okay by me, and already a big improvement over locked voltages, so I left it as is.

So far, after a dozen or so different attempts, I still can't get the voltage to go down when in 2D mode. It always is at 1.3250v according to GPU-Z, which I found to be very precise to read voltages in my own experience. Here's a screenshot of my current settings in RBE:

Do you guys see anything I would've done wrong that would explain this issue I'm having? Is it even possible to do what I'm trying to do?

Thanks in advance for the help, it's much appreciated.

 

[nafets]

If your BIOS was locked initially, all four voltage registers (15 to 18) would read 1.2625v, before you changed them. I could be wrong.

Make sure you have a copy of your original BIOS (dumped from GPUZ) in a safe place.

Working off the original BIOS, try setting Clock Info #s 01, 02, 07, and 08 to 1.083v, in the dropboxes. Do not change any of the voltage register values. Flash the BIOS, and test to see if the card drops from 1.2625v to 1.083v, during 2D state.

If so, then you can go back in and edit the voltage registers. Setting 18 at 1.325v and 15 at something lower than 1.1v.

Also, if you get a moment, make your original BIOS available, and I'll play around with it...

 

[dostov]

If your BIOS was locked initially, all four voltage registers (15 to 18) would read 1.2625v, before you changed them. I could be wrong.

That is exact.

I didn't change them either. What you see in the screenshot I posted is the result of enabling superior powerplay in RBE and checking the box just underneath that says "Decrease voltages". Doing so brings the voltages in registers 15 to 17 to the values you see. Register 18, I changed by hand. It was showing 1.263v and I upped it to 1.325v.

Now, correct me if I'm wrong, but I'm led to believe that the selectable voltages in "BIOS voltage table" are linked to the voltage registers in such a way that if a "clock info" is set (in the dropboxes) to use a voltage that refers to a 0, 1, 2, or 3 (in the BIOS voltage table), then it will use voltages from registers 15, 16, 17 or 18 respectively. In other words, values 0 to 3 are linked to registers 15 to 18, in that order. Right?

Looking back at the screenshot I posted, it would then be correct to assume that if I select 1.083v from the dropboxes of clock infos 1, 2, 7 and 8, then the GPU would use 1.1v when idle (as per the value set in register 15). Wouldn't it?

I think I'll try that and see what it does. Anyways, I played with that feature a lot since yesterday and it didn't prevented me from using my card once, so we can assume it's pretty well implemented. I'll keep you posted as to how it goes.

By the way, the Asus Top BIOS is not the original BIOS for my card. It is available in the TechPowerUP VGA BIOS collection (here) if you want to take a look at it. I flashed it on my card since I had it, to unlock Overdrive (up to 900Mhz on the core). Still, I feel it won't be enough for long since I'll have this BIOS modded pretty high in no time, thanks to RBE.

 

[nafets]

Now, correct me if I'm wrong, but I'm led to believe that the selectable voltages in "BIOS voltage table" are linked to the voltage registers in such a way that if a "clock info" is set (in the dropboxes) to use a voltage that refers to a 0, 1, 2, or 3 (in the BIOS voltage table), then it will use voltages from registers 15, 16, 17 or 18 respectively. In other words, values 0 to 3 are linked to registers 15 to 18, in that order. Right?

You actually bring up an interesting point. I'm doing some more testing to see if the 1.083v dropbox enables register 15, the 1.143v dropbox enables register 16, etc.

Heh, yes, after testing your suggestion, I've come to find that you are right. Where were you when I was originally testing this? My previous assertion of "enabling or disabling PowerPlay" was a bit off. Rather in this case the dropboxes are linked to the register values (but in certain cases this isn't true; I will explain).

Here is a screenshot of one of my working test BIOSes (with a description following) as an example, for others;

With the above setup, the Clock info voltage dropboxes when set to a certain voltage will operate the card at the corresponding register value. This comes out to the 2D voltage being 1.1875v and the 3D voltage being 1.2375v. If I wanted my 2D voltage at 1.225, I'd change the voltage dropboxes in Clock info #s 01 and 02 to 1.263v.

BIOS voltage table   Voltage dropbox value   Register value   Resulting voltage
0                    1.083v                  0x15             1.2125v
1                    1.143v                  0x16             1.1875v
2                    1.203v                  0x17             1.2375v
3                    1.263v                  0x18             1.225v

But as I said before, there is a problem with this. While it works for the HD4870 in this manner, this is not the case with the HD4870X2. The HD4870X2 like the HD4870 shows only four register values (15, 16, 17, and 18), but has eight different (dropbox voltages/BIOS voltage table values). Since I don't have an HD4870X2 on hand, I can't verify how or if there is any connection between the eight (dropbox voltages/BIOS voltage table values) and the four register values.

As such, the current method of using register 15 for your 2D voltage and register 18 for your 3D voltage, still stands as a safe way of setting it for both the HD4870 and HD4870X2. So for whatever states you want to run at the register 15 value, you need to set the dropbox voltage to 1.083v (1.050v for HD4870X2). And to have the card run at the register 18 value, you need to set the dropbox voltage to 1.263v (1.250v for HD4870X2). I still haven't heard from any HD4870X2 users as to what dropbox voltages are to be used to run at the certain register values, so the above values may be wrong.

If anyone has an easier explanation, I'd be glad to hear it. Once again, I'm typing this all up, waaay too early in the morning...

 

[dostov]

Where were you when I was originally testing this?

Well, I don't know... I just heard of RBE 1.19 from a member posting news over at The Raptor Pit. Next time just send me an email!

Meanwhile, I just reflashed to my 4870 and it works as it should now. Enabling superior powerplay on a locked voltage BIOS is bit finicky it seems. I had to click to enable powerplay and check the box to lower voltages, then save the BIOS and reopen it. Then, I modified the voltages and saved it again.

Works like a charm now!

So, what were you saying is the lowest voltage I can run the card in 2D at the defaults idle clocks (500Mhz core)?

Also, do we know what is the maximum core voltage we can achieve like that?

 

[Tatty_Two]

Have you tried changing the voltages that you want to change through Rivatuner?

 

[BAGZZlash]

As such, the current method of using register 15 for your 2D voltage and register 18 for your 3D voltage, still stands as a safe way of setting it for both the HD4870 and HD4870X2. So for whatever states you want to run at the register 15 value, you need to set the dropbox voltage to 1.083v (1.050v for HD4870X2). And to have the card run at the register 18 value, you need to set the dropbox voltage to 1.263v (1.250v for HD4870X2). I still haven't heard from any HD4870X2 users as to what dropbox voltages are to be used to run at the certain register values, so the above values may be wrong.

Yeah, that's pretty much it. I don't know how it works with the "more-than-four" voltage table of the 4870X2s neither, but users can work with this very simply:
If your lowest voltage register value (i.e. the value in register 0x15) is lower than the lowest voltage table/dropdown box value (which should be the case for most users/undervolters), set the dropdown box to the lowest value available for any clock info you would like the lowest register value to apply. Do the same for the highest voltage register value (i.e. the value in register 0x18): If it's higher than the highest voltage table/dropdown box value (which again should be the case for most users/overclockers), just set the specific clock info dropdown box to the highest value available.

Meanwhile, I just reflashed to my 4870 and it works as it should now. Enabling superior powerplay on a locked voltage BIOS is bit finicky it seems. I had to click to enable powerplay and check the box to lower voltages, then save the BIOS and reopen it. Then, I modified the voltages and saved it again.

That's because RBE applies the changes to the BIOS right before saving it (i.e. after the user clicks "Save BIOS...").

Also, do we know what is the maximum core voltage we can achieve like that?

As far as I know, the VT11xx can set up to 2.0 V. Don't worry, I'm sure you'll get much more juice than your card can handle.
Using the voltage registers, RBE can be used to destroy any card equipped with a VT11xx just like that. That's why I keep telling people to be very careful with this! Folks, always keep an eye on your temperatures!

 

[dostov]

Have you tried changing the voltages that you want to change through Rivatuner?

I tried, but for some reason it tells me that I need a digitally signed driver.... I don't know, Vista64/Catalyst 9.1 related maybe... It's been a while since I used Rivatuner to be honest. Time to get back to it I guess. I'll look into that. Thanks!

As far as I know, the VT11xx can set up to 2.0 V. Don't worry, I'm sure you'll get much more juice than your card can handle.
Using the voltage registers, RBE can be used to destroy any card equipped with a VT11xx just like that. That's why I keep telling people to be very careful with this! Folks, always keep an eye on your temperatures!

Thanks for the info. I promise I'll keep an eye out for those things you call temperatures... whatever that is.

Don't worry, I've got it under a more-than-capable water cooling setup.

 

[Tatty_Two]

I tried, but for some reason it tells me that I need a digitally signed driver.... I don't know, Vista64/Catalyst 9.1 related maybe... It's been a while since I used Rivatuner to be honest. Time to get back to it I guess. I'll look into that. Thanks!



Thanks for the info. I promise I'll keep an eye out for those things you call temperatures... whatever that is.

Don't worry, I've got it under a more-than-capable water cooling setup.

If the latest edition of rivatuner is older than the newest cat 9.1's then that would be the issue, roll back to 8.12's (that many actually find faster) and your problem should have disappeared.