Heh, got my Elpida strap stable.
At 1200/2000Mhz, i am getting 975h/s with 896/8/2 and Compute Mode.
At 1280/2000Mhz - 1020h/s.
With the other card, i am getting 1068h/s at 1380/2000, or 1038h/s at 1280/2000.
Can you share your straps?
its not finished, not 100% stable on both cards. I dont have enough free time to update it.
Another tweak I've wondered about is monitoring memory die temps. GDDR5 chips have internal thermal diodes similar to the GPU, and they can be enabled by setting a bit in mode register 7. Knowing the temperature of each memory die could provide useful diagnostic info for problems such as a heatsink not having good contact with the chip.
Yes! Mem temp management is critical to getting Vegas stable - I'm sure it would be hugely useful for stabilizing polaris as well. I now use a rule of thumb of core generally being about 10º cooler than mem, but clearly this is a very rough estimate, and depends significantly on heat sink design (or lack thereof.)
Also might give some sense of the 'asic quality' of the mem (if that's a thing...)
From personal experience, TFAW = 0 is not an issue, but TFAW32 = 0 alongside, causes instability, often seen with Monitor Sleep and background refreshes. Using TFAW32 = 4.
I recently decided to take another look at RAM timings now that many people have been playing with custom timings for several months.
Instead of zeroing FAW/32AW as I do in my strapmod utility, I think it is better to set them low. 7/10 seems to be standard for Hynix straps, while 6/8 is typical for Samsung. My testing so far using 6/8 on Hynix gives the same performance for eth mining as 0/0, while potentially being more stable at higher memory clocks.
I also suspect the field labels may be reversed, so FAW is really 32AW, and vice-verse. In my testing, when I set "FAW" to 8 or 10 while leaving "32AW" to zero, I see no slowdown in ethash speed.
I may update my strapmod when I'm done, but my goal is to finally finish a Linux tool I started working on last year that tweaks timings at runtime. This allows for tuning the memory timing for ethash, equihash, or cryptonight without reflashing the BIOS and rebooting. It has already greatly improved strap testing, as I have been able to modify timings on the fly while mining; I don't even have to restart the miner. I still crash the GPU a lot, as dynamically switching between two sets of good timing will still cause a hang depending on which timings you switch in what order.
I have sort of been under the assumption that in the presence of an invalid value, memory controllers must be calculating t32aw automatically. Every strap I've ever seen (including from mfgs) is out of spec, given that t32aw should always be >= 8 x tfaw, as i understand it.
Btw, would love to take a peek at your tool
Well, 8*0 is 0
There is probably something like that as well, but there is clearly a difference for me, higher instability when both are 0.
Maybe somebody can check it ?
