Vega: thanks but both for practical and security reason, I cannot work this way. Practical because debugging OpenCL crash the GPU very often (GPU memory is not protected by OS like main memory) and i cannot press reboot on a remote rig. And security because it would involve moving my code through network, and that's too dangerous, even with a secure connection.
I already refused such offers for Xeon optims or Threadripper or Xeon Phi for exact same reason. This is very friendly, but i've more reasons to say no than yes.
However i could invest into a Vega if JCE GPU is successful, even if my favorite GPU is RX550 (1/4 speed of vega for 1/8 of price)
Effective hashrate : i observed the same thing with Claymore 10+ (but not 9.x), a pool hashrate a lot lower (~10%) than the displayed one. Even fees deduced. Curiously, this problem occurs only on close source miners, on open ones, where you can check in code there's no cheat, the reported rate is 100% the same (minus fees).
JCE does no tweak, and you can double check pool side.
This is why I counter-argument with Unclewish about Claymore 11.3 being faster than JCE on HD7800 : the displayed number, maybe. The displayed hashrate on my HD7850 rig was 2200 on Claymore 11.3, and 1950 pool side. With JCE, it's 2080 both side. Even after 24h.
"APU not working" : i need more info. Miner crash ? APU not detected ? hashrate is zero ?
Hashrate drops to zero : I already experienced that, and most often on the GPU where the screen is plugged (real or dummy plug). That's when we use too much memory, close to max, the miner starts, then the display driver gets some of the memory (it has higher priority) and never give it back, locking the miner.
Fix : use a slightly lower multi-hash value, or plug no screen on that card.
"Job not found" ok i get it, and that's because JCE is a GPU miner based on CPU miner netcode. A round of CPU is so fast that the job never timeout during mining. A GPU round is often 1 full second, a lot more than the ping. So you can get a stale share. I'll fix that in next version. No need to fix on PU version, only GPU.
I'll add your best configs on the Github page, thanks all (especially UnclWish) for the reports.
nVidia : i didn't even test on nVidia cards. nVidia provides a OpenCL driver so it may work, but JCE is made with OpenCL, not Cuda, so i don't expect it to be that fast.
New! Debian packages Fellow dev eLvErDe ported the Linux zip into two debian packages (32 and 64 bits). No change on miner itself, but should be more Linuxish.
https://github.com/jceminer/cn_cpu_miner