Quote from: jarvis on April 06, 2013, 11:22:41 PM

These babiess are monsters, Large in size and Power hungry. Need some help since this is my first rig and Im a newbie of sorts. Well here is the specs of the rig.

1.   1 x ASUS Rampage IV Extreme LGA 2011 Intel X79 SATA 6Gb/s USB 3.0 Extended ATX Intel Motherboard
2.   4 x PowerColor AX7990 6GBD5-2DHJ Radeon HD 7990 6GB 384-bit x2 GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support
3.   1 x LEPA G Series G1600-MA 1600W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS GOLD Certified Full Modular Power
4.   1 x CORSAIR Vengeance 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 2400 Desktop Memory Model CMZ16GX3M2A2400C10
5.   1 x Intel Core i7-3820 Sandy Bridge-E 3.6GHz (3.8GHz Turbo Boost) LGA 2011 130W Quad-Core Desktop Processor BX80619i73820
6.   1 x SAMSUNG 840 Pro Series MZ-7PD128BW 2.5" 128GB SATA III MLC Internal Solid State Drive (SSD)
7.   (Just in case More is needed or for rig 2.0) 1 x COOLMAX ZPS-1600B (14642) 1600W ATX12V v2.31 & EPS12V v2.92 SLI Ready CrossFire Ready 80 PLUS SILVER Certified Modular
8.   4x PCIE X16 Risers
9.    Win7 64bit OS
10.    Reaper latest released beta for 64bitwin7
11.    Latest Drivers & bios.

Each 7990 has 2 7970 Gpus. ☺

Here is the questions and issues I have come across.

When I install one 7990 everything is groovy, when I install the second the system becomes unstable and errors & various blue-screens of death occur.

Here is what I found out and tried.

Called AMD they said you can only put 2 7990s on a mother board because they do not make the drivers to sustain them, they are already 4 7970 chips when using 2 7990s. I called power-color and they said call AMD and update drivers. Removed old drivers and download the latest stable release and even tried the beta version without success. Flashed the bios to the latest version. With and without risers.

Reaper.conf settings
kernel reaper.cl
save_binaries yes
enable_graceful_shutdown no
long_polling yes
platform 0
device 0
device 1
mine litecoin

Litecoin.conf settings

host mypool.com
port 80
user smpl
pass smpl

protocol litecoin

worksize 256
vectors 1
aggression 18
threads_per_gpu 2
sharethreads 32
lookup_gap 2
gpu_thread_concurrency 21712

My results have been 1.4 Ghz at times or 8,000 to 10,000 khs but starts degradation cycle to 800khs.

Questions.

1.   How can I add successfully one more 7990, for a total of 2 connected to the motherboard per the AMD recommendations?
2.     How do I max out my cards production via the reaper miner? Optimal reaper settings for my rig.
3.   Why the High stale rate of 30-90%?
4.   Is crossfire possible?

Thanks for your help with this. Have many more questions but been up for days working on this rig .

I have practically the same setup - and have issues with the cards crashing too, how did you solve this in the end was it an issue with pushing the cards too hard or was a driver/compatibility issue.

PLEASE could you let me know your software setup - I am on windows 7 so preferable need a windows software requirements support.

Really appreciate it if you could advise me here.

Many thanks in advance