Hello everyone
I am looking for a solution to my problem:
On my pc for gaming
I have 2 rx 480 nitro
I do not modify my bios to take advantage of the latest AMD driver (17.1.2).
I have windows 10.
With my rx480 nitro + @ 1342mhz / 2000mhz memory
I get 27.3 mh / s with the following settings: 1125 mhz / 2200 memory and -100mv
With my rx 480 nitro @ 1276 / 2000mhz memory
I get 24.5
Regardless of the memory setting at 2050, 2100 or 2200. I have no hashrate gain.
I try these settings: 1000mhz / 2000mhz memory -30mv
With this setting -276 mhz in clock and - 30mv I have no loss of hashrate but a gain in W.
Why does my card have no hashrate gain when I change the frequency of memory?
Thank you in advance if you have the solution
cordially
Not modding your BIOS is losing out on essentially free hashing power. Different memory clock speeds have different memory timings associated with them by default in the card's memory timings table.
Like there's one memory timing strap from 1500-1750, then another from 1750-2000, and another for 2000+ etc. As you overclock your memory, it picks and uses the relevant memory timings from the above table.
Some GPU mining algo's depend as much on the memory timing as on the memory clock speed. So as you go higher in clock speeds your card uses progressively looser timings and thus Hashing performance sees no increase. Now these default timings are very conservative but insure 100% stability. What BIOS modding essentially does is hardcode more aggressive timings and force the card to use them at higher clocks.
For instance, you can copy the 1750-2000 timings to the 2000+ memory strap and then you would see an almost linear gain with overclocking. You can also experiment and try even more aggressive timings, like using the 1500-1750 strap for 1750-2000 as well as 2000+ range but stability would become an issue. Experiment and see what works best for you.
