Posts Tagged ‘video BIOS’

Using the Red BIOS Editor to Modify AMD Radeon Memory Timings

30, Jan 2021

Modifying the BIOS of your video card and more specifically the memory timings in order to increase the hashrate you get mining Ethereum is something that most people should do, especially when we are talking about AMD Radeon GPUs, though now a lot of miners also come with the option to optimize timings without you having to modify the BIOS. One very easy way to actually modify the video BIOS is with the help of the Red BIOS Editor (RBE) software that supports BIOS modifications of AMD Radeon GPUs with Polaris, Navi and Big Navi architecture. There are more ways to mod the BIOS for Polaris GPUs that have been available for a while, but for the newer Navi and Big Navi the RBE software is the solution, but here we are going to be modding the ADM Radeon RX 5700 / Radeon RX 5700 XT GPUs as an example. The goal is to be able to optimize the memory timings of these video cards so they can give you about 10% more hashrate for mining Ethereum (ETH), or with other word from about 50-52 MH/s you might get up to about 55-58 MH/s or even a bit more.

Before going out on a modding spree make sure you make a backup of the original video BIOS of the GPU you are about to modify, you will need this in case you mess something up and want to get back to the original settings. A good way to easy backup the original video BIOS is to use the free GPU-Z tool, though you might also find the original video BIOS in the TechPowerUp’s VGA BIOS Collection if somebody already submitted it (if not, you might want to upload it directly from GPZ-Z).

So, start up the RBE software, load the video BIOS you have saved on your computer and click on the VRAM Timings tab. You should see something similar to the image above with the memory timings RAW data and the respective frequency for which it is valid next to each video memory timing string. Since you probably don’t know what these numbers actually mean, what you need to do is just copy the timing string from a lower frequency to a higher one, then save the modified BIOS file (use a different name, do not overwrite the original backup). For RX 5700 XT you can copy the timing string from 1550 MHz and paste it over the higher frequency settings and see if the video card will be stable using these more aggressive timings on the higher frequencies, if it is not stable you can repeat the procedure with the timings from 1800 MHz and so on. You can try even lower, but the chances that it will still work with 1250 MHz are slim to note and you might need a spare GPU to reflash a working video BIOS back to the video card you are modifying.

Flashing the modified or the original video BIOS to the GPU will require the amdvbflash tool, there are different versions available and you need a special one that will work for modified video BIOSes as normally it will not allow you to flash a modded BIOS. The required flasher tools can be download below as a part of the RBE package with the ATI Flash Tool 2.93+ for the RX 5700 and RX 5700XT only, the ATI Flash Tool 3.04 for all AMD GPUs under Windows and also a Linux version should you need one. Flashing under Windows should be done with the command prompt running as Administrator and typing the following commands:

To save the original video BIOS before flashing:
amdvbflash.exe -s 0 original-bios.rom

To unlock the ROM for flashing:
amdvbflash -unlockrom 0

To flash the modified BIOS:
amdvbflash -p -f 0 biosmod.rom

* The number 0 above represents the GPU ID of the first video card, with 1 it will be the second GPU and so on for multiple cards in the same system. You can flash multiple GPUs listing their numbers separated by comas, for example 1,2,3,4,5,6 instead of just a single GPU ID number.

Do remember that after flashing a new video BIOS you need to reboot the computer in order to see the effect and be able to test the performance of the video card with the new settings. If you flash, but do not reboot, the video card will still be using the old BIOS data and nothing will change!

– To Download the latest Red BIOS Editor (RBE) 1.0.7 and the flashing tools…

How to Increase the GeForce GTX 750 Ti Power Target Limit

22, Feb 2014

kepler-bios-tweaker-gtx-750-ti-tdp-power-limit

Nvidia is advertising their new GeForce GTX 750 Ti GPUs based on the new more power efficient Maxwell architecture as being with 60W TDP, but in truth they seem to be much more power efficient than that. A lot of people are already interested in using these new GPUs from NVidia for mining, because the performance that the Maxwell delivers seems to be very good in terms of hashrate per Watt ratio. When you use CUDAminer to mine with the GTX 750 Ti you will notice the card will quickly reach the 100% power target limit and normally you are not allowed to increase the power limiter of the card above the 100% value, you are allowed to only lower it further. The interesting thing here however is that the default TDP limit for GTX 750 Ti is actually set to 38.5W inside the BIOS and the minimum of 78% you can go down to is equal to just 30W TDP and as we’ve mentioned Nvidia is talking about 60W TDP for these cards. The fact that the cards are actually limited to 38.5W by their power limiter is something that can prevent you from squeezing the maximum performance that you can get by overclocking the GPU and/or the video memory of the card, so increasing the TDP limit by modifying the BIOS and reflashing the video card with the modified BIOS can help you with that.

Since many of the GeForce GTX 750 Ti video cards do not have external PCI-E power connector you will be limited to the maximum power that these cards will be able to use due to the 75W maximum of power that PCI-E x16 slot can provide by specifications (66W for the 12V line that you will be actually using, the other ~10W are for the 3.3V line). But even this will provide more than enough headroom since the default TDP limit is not 60W as we though, but really just 38.5W, so lots of headroom for overclocking. In order to be able to modify the BIOS of your video card you will need to first save the original one from the card, you can use GPU-Z for that and make sure you keep the original BIOS as a backup and save the modified one as a separate file (you can also backup the BIOS with the nvflash under DOS if you are having trouble with GPU-Z). Then you need to fire up Kepler Bios Tweaker and open up your BIOS file and edit is as shown in the screenshot above (left is original, right is the modified) in order to get 65.5W as the maximum TDP of the card. After that you need to flash the BIOS back to your card using the provided nvflash, you can download the flasher and the Kepler Bios Tweaker along with a standard BIOS from a reference 750 Ti and a modified version of that BIOS to allow 65.5W TDP from the link below. We suggest that you save the BIOS from your own video card and modify it, also do have in mind that modifying and flashing modified video BIOS to your video card can be dangerous, so you should be extra careful what you are doing and not modifying things that you should not or does not know what they are for!

gtc-750-ti-tdp-limit-increased-afterburner

The procedure described above will work for increasing the power target limit on other video cards as well not only on GTX 750 Ti, however before increasing the limit make sure that your video card cooling can keep the card cool enough. Using the video card fro mining will bring the power target to 100% in most cases even without overclocking the card additionally, so just by increasing it you might e able to squeeze some extra performance even without overclocking it further. The version of nvflash provided in the archive below is the latest one that will work with the GTX 750 Ti as well as with older video cards, it is the DOS version of the flasher as the Windows version of nvlfash does not seem to work properly – it does not want to flash the modified BIOS to the card saying that the BIOS digital signature is wrong. No problems flashing the modified video BIOS though trough the DOS version of nvflash 5.163, so we have only included the DOS version that will work with the method described above. There are two BAT files configured to flash the modified video BIOS and to restore the original version of the included reference design board BIOSes, you just need to run “nvflash your_bios.rom” and confirm with “y” when asked by nvflash (make sure you’ve made a backup of your original video BIOS first!). Again, be aware that video BIOS flashing and modification can be dangerous and can temporary render your video card useless, at least until you reflash it with the original BIOS, so do keep a backup of the original! Also note that increasing the TDP limit beyond the recommended value above could also be dangerous, so be well aware that this modification can be dangerous! Feel free to share your results for overclocking and mining hashrate after increasing the TDP limit of your GTX 750 Ti or another board in the comments below.

– Download the Kepler Bios Tweaker tool and nvflash for modifying your video BIOS…


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