Communication Between the Hashrate and Windows

[Zacon]

I install new windows and hashrate was 720, then i manipulate cg miner settings and hashrate Hardly was 640, then i change settings to original settings, but i cant get first hashrate (720).
The possibility exists that Re install new Windows can get first hashrate (720)?

msi R9 280
Win7 - 64
8gb RAM
Cpu sempron 145
Driver 13.11
Afterburner The latest version

[SomeRelax]

do some tweak in cgminer .conf/cgminer .bat by finding your best setting at https://litecoin.info/Mining_hardware_comparison
if you get a good result, then say hooray
if not, remove cgminer and try again with your old setting
if your hash wasn't what you expect, then try to install a fresh copy of windows
let me know whats the result

[testbug]

No need for reinstalling Windows for this!

I have the same Issue with a asus R9 280x too. I use -10 power settings for mining and a little underclocking of the ram for saveing a little power. not much saveing but ok
Try to add -10 energy lvl to your cgminer config and change intensitiy to 13 if you didnt do that already.