Hi guys.
On my 6950 this patch DECREASES performance about ~10MH/s. So if you have 69xx be careful and check your performance.
I used to have this issue,it turns out you need to apply this change to the kernel.cl file in phatk,poclbm folders (both which u find in kernels folder) and apply this chaneg to this file BitcoinMiner.cl in the GUIminer root folder as well,then you'll be boosted as well.
Hope this helps :-)