I don't know the nomenclature of the ASUS bios, but probably all you have to do is to set the cpu frequency to 375 and set the ram to operate at 1:1 (might be called a 2.0 ram multiplier).
You could probably set the frequency to 400, your cpu will take it and your ram probably will take it.
You didn't say what cpu cooler you have, but when you start overclocking, especially a quad, this will be important. Get prime95, realtemp and coretemp and monitor your temperatures at 375 while you run a stress test with prime95. Read the stickies at the top of the overclocking forum and see what the allowable temperatures for this cpu are.
I'm guessing that you are making the settings more complicated than need be for your level of overclock.
The most important factor for CPU cooling is the heat sink and fan that mount directly on the CPU. This is independent of the fan(s) in the case. Depending on the case that you have, you might or might not need more airflow in the case itself. The CPU heatsink/fan gets the heat away from the CPU, the other fans in the case have to get the heat out of the case. Even with a good heatsink, if the heat can't get out of the case then that's not good. The only way to know is to run the tests and see how it works. Also it depends on what programs you run and how you use the computer. Running prime95 for hours at a time is one thing, running a browser and spreadsheet is a completely different thing.