MSI AB VF Curves for NVidia

[J7SC_Orion]

I was asked at another forum the other day how to best set clocks for a benching session on regular (room) ambient and water-cooling. Many of you already know all this anyway, but for those who don't...a few quick pointers re. MSI AB VF curves for NVidia, and honorable mention of MPT (MorePowerTool) for AMD. MSI AB works also with AMD, but with the more recent models, you are working with two core overclocks making up a range, and for that the AMD Radeon software just works better than MSI AB. That is after you mod the AMD voltages with MPT...For the AMD Giga-G-OC 6900XT, I created a special MPT profile with 500 W max and core voltage of up to 1.243 V (stock is 1.175 V). The relevant MPT profile is included below and it is of course not s.th. you want to run 24/7 - ditto for the MSI AB NVidia steps below.

 

Please note that 'water-cooling' refers not to a single-core AIO but pretty substantial loops (dual or triple core rads at  1080 mm x 63 mm or more , 2x or 3x D5 pumps per loop). For NVidia, the RTX 3090 Strix below is running a KingPin 520 W bios, while the Giga-G-OC RTX 4090 is using the 667 W Galax HoF bios...I also have 1 kW bios for both but for ambient water-cooling that's not such a good idea given that those a true XOC bios with the safeties removed. In addition, MSI AB's config file has to be modified in Notepad for the 4090 when going above 3 GHz.

 

It is best to start with 'stock' core clocks and test out your best (= most efficient) VRAM settings in various games and benches so that you can subsequently focus on core only. Tools such as memtest_vulkan (Github) are excellent for more recent GPUS and VRAM types. Then, pick a reasonably bench such as Superposition 8K or 3DM TSEx with HWInfo open and note your max clocks at max voltage when using the 'normal' MSI AB approach of just using the sliders (full PL, max core voltage on the top two MSI AB fields). Ray Tracing and tensor cores can behave a bit different but the whole point of this exercise is to arrive at a base VF curve profile you can quickly add to or subtract from, depending on the known challenges of a particular bench.

 

Next, with MSI AB open, use 'Ctrl + F' on your keyboard, which brings up the VF curve. This incidentally is a bit like the old ASIC % quality rating of GPU-Z years ago. Now, on the x-axis, choose the highest voltage (remember, this is for benching) you have observed in HWInfo. Click on the corresponding point above and check on the y-axis to see the corresponding core speed. While holding down the 'ctrl' key, slide that point (and with it the whole curve via 'ctrl') up vertically to the observed max in HWInfo you noted before. Then push 'ctrl L' to lock it, then hit escape to get back to the regular MSI AB screen. Now you will see the term 'curve' appear where usually you just see the additional core MHz on the relevant slider. Next step us to save this as 'profile 1' in MSI AB. Then it is testing / benching time again to confirm that you got it just right. Different benches can of course have a different core 'top speed', but I find it invaluable to have a curve profile for the core and most efficient VRAM locked in. You can always load up the locked profile but then override the 'permanent' curve with a 'temporary one' by sliding the point that corresponds to max voltage up or down for a given bench. Finally, I usually got more core speed with the curve than just the sliders on their own.

 

This is certainly not the only method for VF curves in MSI AB - you can pick, move and lock individual points on the curve, truncate it for gaming and limiting the voltage, or change the slope of the curve any which way you like (never mind doing a separate curve for fans if air-cooled). The reason that I prefer this method is because of what I mentioned above: The position and shape of the initial / stock curve relates to what used to be called the ASIC % quality rating...essentially, there is microcode embedded in your GPU which relates to its binning. That is usually done for worst-case scenario (extra wiggle room for the vendor, and assuming so-so cooling) though it does feed into speed step reductions triggered by temps in the driver. I prefer to keep the basic shape of the curve reflecting the specific microcode intact and just slide the curve up or down as a whole.

 

 

 

 

 

 

[J7SC_Orion]

...a bit more data unkeying the different voltage curve steps (each by + 0.025 V) for the RTX 4090. FYI, given the sheer processing power of the bigger Ada Lovelace cores, the higher the core clocks, the more important overclocked VRAM becomes as those cores can actually 'starve'. Also, it is worth repeating:  Do not to use voltage-lock curve oc'ing for regular gaming and other 24/7 tasks (use MSI AB sliders for that) as even a minor load will push the card to the max volts selected on the curve. As always, some fine print do any of these things at your own risk...

FYI , the second pic below was not a curve but done via sliders to give the reader an idea about the actual offset. Max offset for the curve in the bottom pic equates to ~ +338.