47kOhm 1% gives you stable 1100mhz to 1150mhz range 21,5 W Powerdraw including PSU
52kOhm 1% gives you stable 1200mhz 31W including PSU
56kOhm 1% gives you stable 1250mhz 44W including PSU
86kOhm 1% draw way to much and did turn off the device instantly (onboard powersupply is not rated for > 60W) we assumed it to take around 80W.
If you are funny you can try to use an 64kOhms resistor and you will probably get the highest possible frequency of 1300mhz.
At 56kOhm that would give a hash rate of around ~530Kh/s. Also, 2 weeks ago while modding one of my gridseeds, I got real lazy and removed a SMD component from the device (By mistake). The damn resistor is soo small. Either way, I got it back together but it seems to have a solder bridge underneath it. Its been running fine since (I'm scared if I touch it more, I'll lose the SMD component) Does any one knows the value of that resistor? Also, can I leave the solder bridge? Here is a pic:  Thanks! i measured 1kOhm for it. Can someony verify this please? |
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Is your mod any different from the one in the first post? Here is the mod I believe to be the simplest of them all thus far. I found this after a bit of investigation and I have also just confirmed that it's the mod that nemercry has been talking about, testing and providing pics of for days. I have not tried this mod yet but I intend to do so asap. *********************************************************  ********************************************************* A regular 1/8W to 1/4W 1% to 5% axial resistor will work too. Try to shoot for 1% tolerance though. And as usual, try it at your own risk and expense. If you'd like me to make the mod for you, let me know via PM. I am located in the EUS. And there you go wolfey. Yep that is actually the mod how we are doing it. Awesome! Why is this way better than the others, and how fast have you gotten with this mod? 47kOhm 1% gives you stable 1100mhz to 1150mhz range 21,5 W Powerdraw including PSU 52kOhm 1% gives you stable 1200mhz 31W including PSU 56kOhm 1% gives you stable 1250mhz 44W including PSU 86kOhm 1% draw way to much and did turn off the device instantly (onboard powersupply is not rated for > 60W) we assumed it to take around 80W. If you are funny you can try to use an 64kOhms resistor and you will probably get the highest possible frequency of 1300mhz. |
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As wolfey just found my imgur repository, there it is: Thats the mod we are using.  Yep, that is where all the magic happens. Be sure to use a 1% tolerance, to get the best results. And please use SMD ones  |
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Is your mod any different from the one in the first post? Here is the mod I believe to be the simplest of them all thus far. I found this after a bit of investigation and I have also just confirmed that it's the mod that nemercry has been talking about, testing and providing pics of for days. I have not tried this mod yet but I intend to do so asap. *********************************************************  ********************************************************* A regular 1/8W to 1/4W 1% to 5% axial resistor will work too. Try to shoot for 1% tolerance though. And as usual, try it at your own risk and expense. If you'd like me to make the mod for you, let me know via PM. I am located in the EUS. And there you go wolfey. Yep that is actually the mod how we are doing it. |
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Is your mod any different from the one in the first post? Depends on where you draw the line. In the end there is only one way to modify the voltages(e.g. what we all call modding). But there are different ways to reach this. I personally think it is the most time efficient modification you can do. |
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A new run with 2 more modded. The two from the last run are also included.  I clocked down the bad units, which where havin to much hardware errors, to see where they stabilize. It looks like as it has nothing to do with the new units itself, as the HW Errors also occured at another unit(one of the dark gold units). In my oppinion the benefit of tweaking the PLL Voltage, if its even is possible to achieve positive results by doing this, wont be significantly better. Trying to regulate a system, while you do not even know in which direction, cant bring you any further. It is just like playing lotto and thats something i wont bring in here. There is not even one guys here, who actually can proof, that his change in PLL voltage, actually brought him any advantage. It's just ppl. saying, that they assume, that it must be done, if you have done the resistor change. Thats not science, thats not reliable it is an assumption. All PLL tweakings i have done so far, brought me bad resulst. So for now on i just call it bullshit and advice everyone not to play with PLL voltage.Some user wrote me that he thinks, that the mod is not stable, because it has to much HW Errors. I gave him credit for the fact that he recognized correctly, that the Hashrate(e.g. mhz) which the device was running on wasnt "stable". And said yes: There are units where you need to go down with the frequency. till its "stable" again. But that has nothing to do with the mod itself. It's like the 950mhz mod. There are units which are running fine with 950mhz and there are units which are only able to run at 900-913mhz. But still are there a lot of ppl. doing the mod because it still brings you more hashrate than 850mhz or 888mhz. Also if the unit is a bad one and is only stable at 900mhz (with the mod) it must be that it throws also hws at the stock of 850mhz. All what the mod does is increase the range in where your units operate in. A unit which runs bad even at stock clocks will also run bad on a higher clock compared to good units and thats nothing you can change. But lets say you clock a bad unit from 850mhz to 1100mhz and the HWs stay the same, it will be still an increase of 30%. Independant if its a good or a bad unit. |
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@SVK: Thank you. It should be this repository: https://github.com/girnyau/cgminer-gc3355 and i found it in this thread: https://bitcointalk.org/index.php?topic=477709.msg5752544#msg5752544If anyone interested I've modified Andareed's version of cgminer a bit to let you better finetune the gridseed units. There's a big variance in the resistors they used as voltage references so every unit has a different maximum frequency they can run at. https://github.com/girnyau/cgminer-gc3355New frequency table: 800, 813, 825, 838, 850, 863, 875, 888, 900, 913, 925, 938, 950, 963, 975, 988, 1000, 1013, 1025, 1038, 1050, 1063, 1075, 1088, 1100, 1113, 1125, 1138, 1150, 1163, 1175, 1188, 1200 You won't need the ghz ones however unless highly overvolted  You can also define a base frequency as usual, then set per device frequencies by the units' serial number if you want: --gridseed-options freq=888 --gridseed-freq 8D74488A4949=900,8D96227B5449=900,8D7357785355=875 Factory units running since ~48 hours without any hw mods but the fans desoldered: ... |
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24 hours run completed: Cgminer:  Pool:  I am still not sure why the third batch unit (the one on the top) throws that much hw errors but i will investigate and report. |
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I have done the 3 mods on 2 of my pods and seen some benefit locally and pool side. I do find that the choice of pool for testing is important as these multi-coin pools really have poor stratum results. They toss all different kinds of rejected shares upon switching coins. I would suggest for testing mod stability to use a sole coin pool as that has given me better numbers.
Currently running at 1050Mhz stable and I do not have the PLL down to 0.94 yet. Looks like there is more room in these units.
PLEASE READ SO YOU DONT BRICK YOUR DEVICEI just recall everyone: Dont play with PLL Voltage at all if you want to overclock. I did it once and it worked, but i found out that it was just because of the low frequency. As higher i got the higher the Errors did go. So i can advise you to: whatever you do, dont change the PLL voltage. This week i'll gonna post the mod i am doing right now, to show everything its not hard to reach or complicated. But pls dont resolder anything at your PLLs. Also did i calculated some values for the PLL resistors: dont use them, they are wrong! For example: Even on my 1250mhz unit it just gets from 0 HW Errors to more when increasing the PLL. are you surpised? PLL Phase Locked Loop. basically a feedback loop to keep frequency in check stop it from sprilaling out of control. the output is feed back into the input. I just got a lot of requests from people asking me which PLL voltage they should set. And as for my person, i dont mind soldering different resistors for testing purposed, but i do not want people to try something what brings them no benefit at all and probably more work to correct it again. |
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It's currently still running but i wanted to share some results.(yet only 6h runn) first batch (red) second batch (dark gold) third batch (white gold) I modded one of the newest Gridseed units (those with smdleds on it, batch 3) and an older one,batch2. For some reason the newer version of the gridseeds isnt stable like the older ones. After the run is finished i will measure the voltages between some parts, to see if there are any differences... I am not sure if this is just variance or if they did change transistors, which causes this now.  |
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What is their timescale to be delivered ?
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Stable 510kH/s@1200MHz mod of Reggie0, _only_ by replacing R52 with 100k Resistor and C32 with 120k? On the first view this sounds good! @Reggie0: You've said GS takes 28W, do you have measured only the GS with fan or including the power supply? Additionally I'm a bit confused. Here you talk about 510kH/s: https://bitcointalk.org/index.php?topic=519112.msg5954771#msg5954771But later, when it comes to proof stability you screenshot talks about 473kH/s https://bitcointalk.org/index.php?topic=519112.msg5971887#msg5971887Are we talking about different mods? @nemercy: What are your modifications to get 489kH/s@1150MHz stable? It consumes 21W (with fan and PSU) you wrote, so I think its maybe the better choice. 28W is only GS's power consumption without fan. The second picture is for win sandor's 0.6 BTC reward. You can see less than 10 HW errors in 24 hour. It is the same mod, only freq was reduced. BTC: 1gqdzx8iSwUGt3vaoEaPCjvrWo7zKn7PK Give me a little more time and ill give you a run of my 1250mhz and of my 1150mhz units. 24h each. I was able to setup a headless machine now and can let them run 24/7 now. Probably i'll get a higher stable rate. Lets see |
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I have done the 3 mods on 2 of my pods and seen some benefit locally and pool side. I do find that the choice of pool for testing is important as these multi-coin pools really have poor stratum results. They toss all different kinds of rejected shares upon switching coins. I would suggest for testing mod stability to use a sole coin pool as that has given me better numbers.
Currently running at 1050Mhz stable and I do not have the PLL down to 0.94 yet. Looks like there is more room in these units.
PLEASE READ SO YOU DONT BRICK YOUR DEVICEI just recall everyone: Dont play with PLL Voltage at all if you want to overclock. I did it once and it worked, but i found out that it was just because of the low frequency. As higher i got the higher the Errors did go. So i can advise you to: whatever you do, dont change the PLL voltage. This week i'll gonna post the mod i am doing right now, to show everything its not hard to reach or complicated. But pls dont resolder anything at your PLLs. Also did i calculated some values for the PLL resistors: dont use them, they are wrong! For example: Even on my 1250mhz unit it just gets from 0 HW Errors to more when increasing the PLL. |
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- Enable VID1: Short R336 (original VMOD)
- Increase DVDD to 1.4V: Cut R46 (0R jumper) and replace with 2.94k
- Increase VDD_PLL to 1.2V: Add 27.4k on top of R212 (27.4k || 10k = 7326R)
For reference, the default VDD_PLL is 0.8 x (R211 + R212) / R212, or 1.092V.
Not getting HW errors at 1000 MHz, but I haven't tested long term because I only got my units yesterday. I'm sure 1100+ could be achieved by increasing DVDD using the above method.
It's currently stable (no HW errors, short term) at 1250 MHz (529 kH/s) at 1821 mV, with R46 being 14.7k. Here are my R46 values and measured DVDD: | Resistance (R) | Voltage (mV) | | 4.32k | 1450 | | 5.90k | 1509 | | 7.79k | 1581 | | 12.1k | 1734 | | 14.7k | 1821 |
I think I'll stop there before I damage anything Edit: here is a microscope shot of the mods Blue: R336 Green: R46 Purple: R212  @Mixdio: Could you explain me which benefit i'll get when i give it a higher PLL voltage ? Doesnt make sense for me to higher the voltage there ? Would be nice if you can help me on that here. |
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Ich freue mich drauf, komme aufjedenfall vorbei!
Gruß
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these 4 resistors on the vrm, are they all selectable?
would it be possible to set 4 different voltages,
and select them in software?
so you could rund 30W/500kH now
but switch later to 10W/400kH
I have to admit that i dont get the profit from doing this . Acutally (as far as i know), you need to hard mod those voltages. Regards |
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I was about to settle in and do the other mods but if the 533 turns out to be legit and sustainable,,,, i mean DAMN!
I can assure you that the unit is stable with that value. But to be honest at the actual power draw(31Watts), its not really worth the effort. (Also with nearly zero HW-Errors, its just a question of the voltage given.) ( I will post a description how to do those modifications next week, so everyone can do it itself if skills are available.) Yet not a 24 h run, but i only got my desktop for this. And Everytime i want to test another modification i need to turn it off...  (I will point it to a headless machine the next days, and deliver the proof) |
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