Haha, this is probably gonna fuck up your day, but check the pool.
I already received a mail the pool is only displaying half the hashrate of the miner...
It's NOT the pool
pool is not accurate..
refreshing page from time to time, my combined r9 390 and 5870 fluctuates from 1.7 GHs to 3GHs but sticks to more or less 2.5 GHs.
http://s11.postimg.org/6rpjbx2sj/5870a.jpgI would run them separately and check your rates. I imagine most of that hash rate is coming from your r9 390 when you run them together. The vector setting defaults to 2 instead of 1 messing with the numbers on my 5770. I added -v 1 to my bat to fix it. My 5770 pulls around 393Mh/s per cgminer, pool shows between 300 - 450 depending on luck. The 5800 series should be twice that if I remember correctly.
Also look at your acceptance rate. On the left I assume is your 290 started at 9:34:07 with 1032 shares accepted. On the right is your 5870 started at 9:34:09 with only 472 shares accepted. If they were started that close together your acceptance rate should be within 10-20% I would think. That makes me think it is the vector switch.
My 5770 runs pretty good on a diff of 1 with a drop of the mem clock to 600, maxing out the gpu engine @ 960, and an intensity of 14. It runs at 61c. It's an old card that I'll run until it drops.
I couldn't run my r9 380 & my 5770 together effectively. The high diff caused my 5770 to throw out "share above target" lowering my acceptance rate. You can only see it in verbose or debug since it isn't a reject or a hardware error. Just thought I'd mention it in case the 5800 is doing the same thing. You might be able to squeeze more out of it.