1. Who knows.. try it and see. But I doubt it
2. That value depends on the memory product itself so I can not say for sure however 1.55 is typically ok. You need to check with the memory company on exact limits
3. The CPU GTL is a factor of VTT or FSB Termination Voltage. The NB GTL is a factor of the NB Voltage. It is sometimes needed to run stable however if it will run stable on AUTO it is best left there. If not stable then use the feature however the dangerous voltages to change are CPU PLL and FSB Termination. If you change those and include the GTL multipler you can fry a proc without it ever getting hot or close to max temp.
If it will run AUTO stable, put them on auto. If not set them back
4. Nope, a 400FSB CAS 4 clock at 1000 and tRD5 is in the hot zone. The only better you can do is 1T and I doubt it will do that with tRD5. Since you have established a correctly defined hot-clock, every FSB higher than 400 will deliver 2x the punch but will also become more and more unstable very quickly.
The only other possibility would be a 450MHz x8 clock on the same memory speed and timing with a 333MHz strap but I think you must have 1200 memory to do that so you are probably maxed out now.
Keep in mind.. components must break in so you may become unstable and not be able to run those numbers in a few weeks time. Its the luck of the draw in that respect
speaking of hot clocks.. check out the latency on this bad boy
