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Custom ROM How-To Straps / Timings (RX | Polaris)

SunyataSunyata Member Posts: 35 ✭
in Mining
Hello all,

I've been becoming more and more curious about how to make my own custom ROMs. I've spent a lot of time reading the forum and find a lot of talk about making ROMs especially regarding the new RX series cards. I'm aware of the PolarisBiosEditor and have messed with it a little. I am already comfortable with flashing BIOS.

What I am most curious about learning more about is the memory portion. As I've read people are using terms such as "memory strapping" and "timings." Can someone explain these terms? Or point me in a direction where I can obtain a better understanding? Also, I have some questions regarding these terms and custom ROMS in general...

Are there any rules/guidelines for modifying the straps/timings settings?
Is there anything you should never do?
Is there anything you should do right away?
Is there a risk to permanently damaging hardware by modifying the straps/timings?
If there is a risk, how is it best mitigated?
What's the safest way to go about experimenting with these?


Furthermore, if someone would like to layout a general/basic how-to introduction as for how they approach making a new custom ROM for a card, that would be happily welcomed!

Thanks guys! :smile:
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Comments

  • hasherhasher Member Posts: 642 ✭✭✭
    I think @Heliox would be the best person here to answer these questions, but he probably wouldn't want to give out his secrets :(
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  • cscheatcscheat Member Posts: 147 ✭✭
    Careful mate. I bricked 2 gpu already
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  • Zorg33Zorg33 Member Posts: 220 ✭✭
    edited August 2016
    Lot of reading and trial and error testing.
    That's the only way...
    You can revive bricked cards with the 1-8 pin jumper trick as far as I know, I haven't tried it yet tho. Someone mentioned it.
    Update: here
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  • TruthchanterTruthchanter Member Posts: 549 ✭✭✭
    with reference 470 4gb, I used Polaris Bios Editor on the stock bios rom. All I did was copy the memory strap timing (the code of digits) from the 1500 value and pasted it into the 1625, 1750, and 2000 values. This gave me a huge boost in hashrate.

    You have to get win7 or win10 ready for custom bioses with some easy steps found in other threads. and flash with atiflash 2.74
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  • LogicaluserLogicaluser Member Posts: 214 ✭✭
    Will try to explain the concepts simply.
    The BIOS has a table with the timing settings for various clockspeed ranges.

    a "timing strap" is the settings used within a particular range.
    The 1625 values are used for 1501-1625mhz, the 1750 values used for 1626-1750mhz, etc...

    These are comparable to the say... 9-9-9-24 timings you see for system RAM https://en.wikipedia.org/wiki/Memory_timings

    Unfortunately, for GPUs it's not as easily accessible nor labeled.
    What most do is simply copy the settings from one range to the ranges above.
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  • zawawazawawa Member Posts: 27 ✭
    Does anybody know the specifics of values of memory strap timing for RX 480? I'm just very curious...
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  • TruthchanterTruthchanter Member Posts: 549 ✭✭✭
    Logicaluser said:

    Will try to explain the concepts simply.
    The BIOS has a table with the timing settings for various clockspeed ranges.

    a "timing strap" is the settings used within a particular range.
    The 1625 values are used for 1501-1625mhz, the 1750 values used for 1626-1750mhz, etc...

    These are comparable to the say... 9-9-9-24 timings you see for system RAM https://en.wikipedia.org/wiki/Memory_timings

    Unfortunately, for GPUs it's not as easily accessible nor labeled.
    What most do is simply copy the settings from one range to the ranges above.

    Ah okay this helps me understand why clocking my memory at anything above 2000 was greatly decreasing my hashrate.

    Is there a way to add another timing like 2125? I may have to experiment
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  • cscheatcscheat Member Posts: 147 ✭✭
    simply speaking

    1500 = tighter timing
    2000 = looser timing

    same applies to DDR3/4 ram OC in gaming

    in order to get it stable we have to up the voltage or else we will receive invalid shares/ red warning in claymore
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  • MrN1ce9uyMrN1ce9uy Member Posts: 190 ✭✭
    Maybe the OP is asking about custom timings, not just copy/pasting.
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  • Wolf0Wolf0 Member Posts: 329 ✭✭✭
    MrN1ce9uy said:

    Maybe the OP is asking about custom timings, not just copy/pasting.

    If he is, he probably isn't going to find a lot of info when folks like me get paid for custom work.
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  • MrN1ce9uyMrN1ce9uy Member Posts: 190 ✭✭
    Wolf0 said:

    MrN1ce9uy said:

    Maybe the OP is asking about custom timings, not just copy/pasting.

    If he is, he probably isn't going to find a lot of info when folks like me get paid for custom work.
    I can understand that. It's quite complex and most people wouldn't take the time to mess with it even if all the information was readily available.

    But there are 41 pages of discussions on this subject over @ bitcointalk.org (which you know) - https://bitcointalk.org/index.php?topic=1758267.0
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  • Wolf0Wolf0 Member Posts: 329 ✭✭✭
    MrN1ce9uy said:

    Wolf0 said:

    MrN1ce9uy said:

    Maybe the OP is asking about custom timings, not just copy/pasting.

    If he is, he probably isn't going to find a lot of info when folks like me get paid for custom work.
    I can understand that. It's quite complex and most people wouldn't take the time to mess with it even if all the information was readily available.

    But there are 41 pages of discussions on this subject over @ bitcointalk.org (which you know) - https://bitcointalk.org/index.php?topic=1758267.0
    I know - my owner and I wrote the first published decoder, IIRC.
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