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Discussion Starter · #1 ·
all testing was done with 3 reference 970's (2 6-pin) with xspc waterblocks if it matters.

the best I could do Maxwell II bios editor guide.
I.Introduction
II.Getting started
1. Common tab
2.Voltage table tab
3.Power table tab
4.Boost table tab
5.Boost states tab
6.Clock states tab

I.Introduction.
let me start by saying that I am no professional. I have no affiliation with the creators of the Maxwell II bios editor or nvidia. From a technical standpoint I have no qualifications as to what I am talking about in this guide. Now with that out of the way I have been modifying my bios since the 660ti or kepler bios editor for thoes who arent firmiliar. I feel that i am qualified egnof to provide a guide explaining how you can go about doing so yourself instead of having to do what most everyone els has done. for example saying well F it lets see what happens and crossing your fingers or searching for hours through all 586 pages of a fourm hoping someone will talk about there experiences with l2c overclocking and syncing or whatever it is your trying to find out
II.Getting started
First things first. you will need a Nvidia maxwell GPU. You should spent some time with this card with its bios in its factory state so you can get to know its behaviors. once you feel you have squeezed all you can out of your card you should set you max stable overclock and do the following.
wile under load take note of
1. the factory fan profile and the tempature associated with it
2. the gpu core voltage and clocks associated with it
3. perfcap reason using gpuz or similar
4.voltage limit, power limit, ov max limit in evga percision or similar. are they on
I will not be going over how to overclock your card or how to use software such as evga percision or afterburner i also will not be going over how to test your overclock for stability these are things you should know at this stage. If you are atempting to modifying your bios without this knowledge you are making a mistake.

BEFORE WE GET STARTED DO NOT USE THE SETTINGS IN PICTURERS BELOW. THEY MAY NOT WORK FOR YOU AND MAY NOT BE VALID .THEY ARE JUST A VISUAL REFERENCE

1.Common tab


-Basic clock settings
1.TDP Base Entry, 3D base entry,boost entry in MHz : allow you to match you Base clock and Boost clock if you would like to do that but honestly I feel there is no need to change any of them for gaming purposes
2&3.TDP Base Clock and 3D Base clock in MHz : this number is your lowest gpu core clock wile in 3d. I also feel there is no need to change any of them for gaming purposes
4.Boost Clock in MHz : if you have followed this guide sofar you should know your max stable core overclock you should enter it in this box ( this may change by a small margin once we get to the Boost Table tab section 4)
5&6. Temp Target & max temp target : thies directly relate to your overclocking software temp target value
7&8. Boost Limit: somtimes locked by default (explanation in section 5) regulates maximum boost clock
9. Memory Clock: speed memory is running at in MHz. you should set this to you max stable memory overclock.
10. GPU Clock Offset + 13MHz.you can use this to increase your tdp,3d and base clocks in 13 step incriments. this button is not needed you should leave it alone.
-Fan Control (Experimental)
1. RPM 11,12,13: rpm of fan corosponding to settings 2 and 3 (below it). leave it alone unless you have an intimate relationship with your gpu fan and know its percentage to rpm ratio.
2. TMP 11,12,13: tempature in C corrosponding to settings 1 and 3 (above and below it). you can change thies to adjust your fan profile from the bios level
3. PER 11,12,13: power suplied to fan in percent. same recomendation as 1
4.PER01:minimum fan power in percent PER02:maximum fan power in percent best left alone unless you want quiet. Some users have reported errors if minimum is set below 20 this will depend on your card
4. RPM01, RPM02 same as above but in RPM same recomendation as 1

2.Voltage Tab


1. maximum gpu core voltage in mV. (1281.3=1.281v) getting this setting will take either some experimenting or some research. Some card makers hard lock this setting very low. also keep in mind the max the sensor will read is a max of 1.275v in software wile reading a max of 1.31v with a voltmeter at the card. however most cases 1.250v has been sufficient for 1500mhz core clocks. so research what your cards max hard limit is and move slider to that value to save many hours. if you have a reference 970 its 1.281v
smile.gif
also if cpuz pops a vrel (baby blue) under perfcap reason you went to far and need to work your way down until vrel stops
2. overvoltage limit. directly relates to overclocking software. leave left alone and set right to max hard limit
3. external voltage regulator. set both sliders to max hard limit
4&5. min max voltage for different p-states leave left alone set right on all to max hard limit
6. CLK 01-74. Clock States. from CLK63-74 put left and right to max hard limit there will now be a large voltage gap between CLK62 and CLK63 so smooth it out going from CLK 63 setting each lower clock state 62, 61, 60, 59, 58.... and so on one voltage step lower until they match up. some reported crashes from having to steep of a voltage drop.
the very bottom slider with no label i was informed is the voltage for the memory i was also informed that it is hard locked and therfore not adjustable no mater how hard you try

3.Power Table Tab


first off
a pci-e motherboard slot can provide 75watts (75000mW) MAXIMUM.
a 6pin and an 8pin can safely suply 150w (150000mW) with a high amp single rail psu but it is up to you what you feal safe with. (a 6 pin is rated at 75w and an 8 pin at 150w) but looking at the bios stock they are willing to exceed the rated spec
also this is were most bios differ from eachother. some have 8 sets of numbers and some 9 all bios list 6pin and 8pin even if its not on the card. this is one reason i use 150000 for 6 and 8 pin its just easier and causes no harm
being that there can be a different number of paramiters the easiest way to do this is to do the first 3 then the last 3 that way the remaining one will be a pci6 or 8 pin
1.TDP: Min(mW) : leave it alone Def(mW) & Max(mW) set to 300000.the card will never use this and it will clear the potential for a problem later
2. internal rail: nobody knows people have played with it. does nothing anybody is aware of. leave it alone.
3. pci-e motherboard slot Min(mW): leave it alone Max&Def(mW) set to 75000


ok the last 3
4.power target. this is how much you card is allowed to comsume in mW leave min alone
def should be 6pin+6pin+pci-e if you have 2 6-pins . total should not exceed max TDP(mW)
5.unknown dont touch.i did no result
6. unknown dont touch.i did no result
the boxes you have not touched yet are your pci-6 and 8 pin leave Min alone i set Def to 100000 and Max to 150000 but what you realy need to do is look at the percentages and match your pci-6 and 8 pin Def and Max percentages to your power target Def and Max percentages
4.Boost Table Tab


there is only one setting on this tab and what you should do with it is move the slider until 74 is the same or as close as possible rounding down to your max stable core overclock. make sure you go back to the common tab and that you match the Boost Clock box with the value you ended up with at 74.

5.Boost States Tab


GPC=core clock L2C= cache XBAR= crossbar SYS=system
i have done a good amount of testing with overclocking and matching GPC XBAR SYS and L2c my results are as follows
for every +100mhz to L2C SYS XBAR = +20 points in heaven extreme settings 4096x2160 and 100 points in fire strike 4k
for ever 50mhz core clock i saw the same gain
i saw no benifit from matching GPC to L2C XBAR and SYS i also found that not syncing L2C XBAR and SYS caused stutter
so match max L2C,XBAR and SYS and match GPC to max stable overclock
if you want to overclock L2C,XBAR and SYS you must do it slowly reflashing and testing until max stable overclock is found. take your time. higher numbers arent always better and can be slower so benchmark multiple times. save and compare results
any changes made to P00 must be made to P02 or you may experience crashing.
if gpc xbar l2c and sys all match it unlocks boost limit clock in common tab

6 Clock States tab


i have found no information on this and have not found the need to try fooling around in it for myself
and one more thing. I have found the easiest way to flash is disable drivers the drag your bios onto nvflash.exe I see a lot of people having issues but this has always worked for me once you run -protectoff
 

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Discussion Starter · #2 ·
I would like to keep this thread free of bios downloads and requests for them this is about education and saving time thanks
and if anyone would like to educate me further I would love to do some testing then update the guide
 

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Thanks for the guide, would be looking for one when I decide to mod my GTX 970 BIOS.
 
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Discussion Starter · #4 ·
don't delay. mod away. the 970 bios is a real bottleneck especially when you start looking at factory overclock versions. I and others have found that the factory overclock versions lower the XBAR L2C and SYS to achieve the higher core clock
 

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Great guide, will look into it
smile.gif


Have recently built a new rig with gtx 970 - ASUS GeForce GTX 970 4GB TURBO.
Have never bios mod before, so I feel a little shaky, but I guess thats the beauty of it, just baby steps and you will get there right
thumb.gif
 

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When I open my gm200 bios in the keppler editor and save it to make the hidden sliders appear I have no longer the fixed voltage tickbox?
 

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With respect to the guide and it's warning that "if Gpuz pops a vrel (baby blue) under perfcap reason you went to far and need to work your way down until vrel stops"

This refers to the voltages in the voltage table right?

For my GTX 980Ti Amp Extreme I've noticed I needed to severely curtail the maximum voltage to 1243mV or
I get instantaneous Vrels.

Do Vrels directly cause throttling? Is there anyway to modify the VBIOS and raise or eliminate the Vrel limit?

What's the max core voltage on a Maxwell 2 GPU? Is it the same for 970's, 980's, 980Ti's and Titan X's?

One last question what's the difference between VOp and VRel? If you hit the VRel limit before the VOp limit or vice-versa what's the point of having both of them active?

Thanks for the Maxwell BIOS editing guide.
 

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Thanks, interesting info about L2C, XBAR and SYS here. Worth to dig into this. Interesting also that the ref values here are all 1392.5
Will need to do some testing there.
 

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Quote:
Originally Posted by flexy123 View Post

Thanks, interesting info about L2C, XBAR and SYS here. Worth to dig into this. Interesting also that the ref values here are all 1392.5
Will need to do some testing there.
I've had problems going too far w/the L2C value -- I had problems booting @ 1479 and persistent driver resets while working in Firefox w/GPU acceleration enabled. Because of this I now have my SYS and XBAR set to 1479 and my XBAR @ 1447.

Is it possible that if I dropped the XBAR/SYS/L2C values I could go higher on my GPU core clock? Would that be worthwhile? What clock domain is the SYS value controlling?
 

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There is very little info out there, but what I dug out was
>>
GPC = "General Purpose Core" - This is the primary core of your GPU
L2C = "L2 Cache" - This is the on core memory that your GPU core has access to. Running it at the same clockspeed as the core itself nets a large gain.
XBAR = "Memory Controler Crossbar" - This is the bus speed of the memory controller that talks to the core.
SYS = "System" - This is the rest of the card that isn't tied to another clock domain.
>>

In my case, I discovered that core clock (no matter what voltage) above 1392 gives me blackscreens in The Witcher 3, so I currently limited all my clocks to 1392.5 and also set all those max values to it. Which interestingly is also what's in the reference BIOS of the GTX 970.

I think it is definitely the case that dropping the values there might yield you higher GPU clocks, since this is exactly what all those vendors who make factory OCed cards do! On my EVGA, some values there are as low as 1344, but then a higher GPC. So or so, I have all of them at 1392.5 now since currently I am not chasing after overclocks but want highest stability. (Amazingly my EVGA which craps out at 1418 in The Witcher needs only 1.125V at 1392 and is then stable....)
 

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8051, forget about changing those values. I wrote above that I set them all to 1392.5, way too instable. I set the XBAR, SYS etc. values back to what they were before. I guess there is a reason that they set them to what they were before. Otherwise you're just opening a can of worms messing with those values... (I just did some testing)

PS: You got your name from the microcontrollers? I used to program 8051 micro controllers back in the day
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Quote:
Originally Posted by flexy123 View Post

8051, forget about changing those values. I wrote above that I set them all to 1392.5, way too instable. I set the XBAR, SYS etc. values back to what they were before. I guess there is a reason that they set them to what they were before. Otherwise you're just opening a can of worms messing with those values... (I just did some testing)

PS: You got your name from the microcontrollers? I used to program 8051 micro controllers back in the day
smile.gif
Yep the old 8051, a Harvard architected MCU. We used the 80251 though, because it was much faster.
 

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Quote:
Originally Posted by flexy123 View Post

There is very little info out there, but what I dug out was
>>
GPC = "General Purpose Core" - This is the primary core of your GPU
L2C = "L2 Cache" - This is the on core memory that your GPU core has access to. Running it at the same clockspeed as the core itself nets a large gain.
XBAR = "Memory Controler Crossbar" - This is the bus speed of the memory controller that talks to the core.
SYS = "System" - This is the rest of the card that isn't tied to another clock domain.
>>

In my case, I discovered that core clock (no matter what voltage) above 1392 gives me blackscreens in The Witcher 3, so I currently limited all my clocks to 1392.5 and also set all those max values to it. Which interestingly is also what's in the reference BIOS of the GTX 970.

I think it is definitely the case that dropping the values there might yield you higher GPU clocks, since this is exactly what all those vendors who make factory OCed cards do! On my EVGA, some values there are as low as 1344, but then a higher GPC. So or so, I have all of them at 1392.5 now since currently I am not chasing after overclocks but want highest stability. (Amazingly my EVGA which craps out at 1418 in The Witcher needs only 1.125V at 1392 and is then stable....)
I wonder if the XBAR is more or less just cross-coupled multiplexers that connect the memory controller(s) to the core/L2C?

Maybe the SYS (system) corresponds to the part of the GPU that communicates w/the PCIe bus?

I'm running 1.281V through my 980Ti to get 1468 MHz. stable, I've run all the way up to 1.3V in BIOS at which point I think the VRM's were having thermal issues, but it could've been the overclocked XBAR as well. I currently have my XBAR/SYS/L2C @ 1447/1479/1479.

I wonder how the memory controllers are configured in modern video cards? Do they read/write in quad-word quantities?
 

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Quote:
Originally Posted by 8051 View Post

I wonder if the XBAR is more or less just cross-coupled multiplexers that connect the memory controller(s) to the core/L2C?

Maybe the SYS (system) corresponds to the part of the GPU that communicates w/the PCIe bus?

I'm running 1.281V through my 980Ti to get 1468 MHz. stable, I've run all the way up to 1.3V in BIOS at which point I think the VRM's were having thermal issues, but it could've been the overclocked XBAR as well. I currently have my XBAR/SYS/L2C @ 1447/1479/1479.

I wonder how the memory controllers are configured in modern video cards? Do they read/write in quad-word quantities?
I am not familiar at all with those internals, besides the basics. Ever since I have this card I am suspecting VRM related issues as well.
I know that one of these clocks, possibly SYS also refers to the CUDA processing clock.

My normal testing routine is with Heaven benchmark, where I can otherwise easily OC to 1481, but right now I am focusing on this particular scene in The Witcher 3 which seems to cause many people problems.
 

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I've looked over the VBIOS for several different models of 980TI's (the factory o'clocked models). It's interesting they all seem to have different values for XBAR/L2C/SYS. Could it be that these values are customized for each individual 980Ti? Or at least for each model of 980Ti?

I'm going to revert back to stock XBAR/SYS/L2C and see if it resolves my boot problems and FPS stutters.
 

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To me it seems that all factory OC cards take their factory OCs at cost of those clocks, they're all lower values than stock/reference. So I'd definitely set them back to what you had them before. I mean I tested yesterday, set them all to 1392 and Heaven benchmark crapped out after 10 mins. Then I set it back to what it were before and run it without problems, at the same (main) clock speed. That's why I said "can of worms" touching these values
smile.gif
 

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Quote:
Originally Posted by flexy123 View Post

To me it seems that all factory OC cards take their factory OCs at cost of those clocks, they're all lower values than stock/reference. So I'd definitely set them back to what you had them before. I mean I tested yesterday, set them all to 1392 and Heaven benchmark crapped out after 10 mins. Then I set it back to what it were before and run it without problems, at the same (main) clock speed. That's why I said "can of worms" touching these values
smile.gif
Actually, in my research I found some of the factory overclocked VBIOS for the 980Ti's had higher XBAR/L2C/SYS values:

a. EVGA classified XBAR=L2C=SYS = 1455.5

b. Zotac AMP! Extreme XBAR=1431 L2C=1447 SYS=1479 (what I've got)

Two different ASUS models:

d. ASUS XBAR=1459.5 L2C=1492 SYS=1525

e. ASUS XBAR=1393 L2C=1424 SYS=1456

I believe the stock, reference 980Ti has the L2C/XBAR/SYS set to 1392 as you pointed out.

It turns out my problems had nothing to do w/o'clocking the L2C/SYS/XBAR on my 980Ti and everything to do w/an unstable o'clock on my CPU. I managed to crank the
XBAR/L2C/SYS to 1479 @ 1.87V Vcore and it seems like games run smoother w/those values than the stock ones.
 

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wow neat. i guess now we know a little more of what each of the things were in the bios editor.

if anyone was curious what my 980 ti looks like without wanting to open up a bios file here are some pictures for ya





EDIT: this is how you beat a 1070 ^_^
 

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I've been experimenting w/the L2C/SYS/XBAR values in my 980Ti. I was hoping by lowering them I could increase my core overclock. The strange thing is that lowering them resulted in less ability to overclock the core.

@ L2C/SYS/XBAR setting of 1394 MHz, I couldn't even get 1443MHz core clock stable, but at 1494 MHz L2C/SYS/XBAR I can overclock to a 1493 Mhz. core. But this doesn't make any sense does it?
 
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