So 1.75 it is. Thanks for the answers, they've helped a lot.
After all is said and done, the problem seems to be that the cpu isn't playing nice with either the motherboard or the memory. The answer will be to ultimately get a newer motherboard and faster memory and hope that does it. For now, the answer is putting the old CPU back in, since it works with my current setup just fine.
*sigh* speed denied... :)