bus speed issues?

[point5]

Yeah, I understand the bus speed should be just fine. No argument there. What I am saying though, is that there is something wrong with putting 3x7970 in my setup. So it is either a ocl, hashcat, driver, or hardware issue. One GPU is always twice as fast as the other two. Even when I only run 1 gpu at a time, gpu 3 is always twice as fast. Here is an example when all 3 are running:

GPU-Loops: 1024
GPU-Accel: 800
Password lengths range: 8 - 55
Platform: AMD compatible platform found
Watchdog: Temperature limit disabled
Device #1: Tahiti, 2048MB, 0Mhz, 32MCU
Device #2: Tahiti, 2048MB, 0Mhz, 32MCU
Device #3: Tahiti, 2048MB, 0Mhz, 32MCU
[s]tatus [p]ause [r]esume [q]uit => s
Status.......: Running
Hash.Target..: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
Hash.Type....: MD5
Time.Running.: 5 secs
Time.Left....: 4 days, 10 hours
Plain.Mask...: ?1?1?1?1?1?1?1?1
Plain.Text...: ***aaaaa
Plain.Length.: 8
Progress.....: 85563801600/6634204312890625 (0.00%)
Speed.GPU.#1.: 4484.4M/s
Speed.GPU.#2.: 4483.7M/s
Speed.GPU.#3.: 8233.8M/s
Speed.GPU.#*.: 17318.2M/s