variance in H#/s

[g7g7g7g7]

Hi there, I set up bitcoin the other night using GUIminer and have been keeping an eye on things but the variance I am getting in MH/s is ridiculous. My setup is as follows,
MOBO- m4a89GTD
GPU- 6850 x2
CPU- X4 955BE
running on win7

with one card enabled I am getting 180MH/s
with both enabled (as seperate miners) 130/130 (260)
however when I leave my computer and check on it later this has dropped to under 100 per card until I check on it. I have no power saving options enabled I am just turning off my monitor and leaving my computer running. So I have looked around and  cant find a definite answer so I thought it best to ask.

1. Is there any way to get 200% with two cards running or am I missing some setting?
2. When left unattended why does the rate at which I mine decrease so fast, I mean 10 mins after I last checked on it, it drops again?

any help would be greatly appreciated, thanks
Gav.

[true_source]

do you perhaps have some kind of screen saver that uses the graphics card? I mean, if you turn off your monitor when leaving the machine you wouldn't probably get it if theres a screen saver working. and most ppl move the mouse a bit when bending over the desk.

I would also (if it's not a screen saver) check my machine for malware. There might be something on your computer that's waiting for you to leave the computer(like a screen saver) to do it's "work" without you knowing.(Botnet computers tend to "live" longer if the victim does not know it's infected)

[g7g7g7g7]

Nope no screen saver, I will check the power management options again though.

I ran malwarebytes a couple of days ago and nothing there, unless something came in when I downloaded bitcoin I think I am fine, I will check again though, thanks.

[g7g7g7g7]

Just checked everything and it all seems to be fine, I did notice that I was sitting at a steady 300MH/s.

It just seems strange that it is going between 200-300 for no reason.

[Darknesss]

Unplug the computer?

[Bitsausage]

Try a different pool, the pool you are using could be giving connection errors.