There is a chance that you will be able to install RmClock and turn off the EIST with it. I know that HP won't let you do it in the bios.
There are some things that you need to consider first. HP and Intel have a goal that seems to drive everything they do lately. They want your PC to be quiet. So, they put EIST into most of their processors to help accomplish that. Instead of getting a good heatsink and fan they would rather slow down the processor that you paid dearly for. That may not make sense but stay with me and I'll splain it.
EIST works by lowering the multiplier and voltage on a regular basis. It is like clockwork. Up and down.....Up and down. That reduces the heat generated by the CPU. Now you could just turn it off with RmCLock. I am fairly certain that you would be able to do that. BUT!!!
But!!! That system was designed with the assumption that the 630 would be constantly throttling up and down. HP is counting on it doing that to keep it cool. So it is probably not a thermally advantaged case and the last one I looked at had a cheaper cpu fan and heatsink than the intel stock one.
So, the bottom line is that if you are going to turn EIST off, you need to have something like speedfan or pc wizzard to watch the temps for a while and make sure you haven't shot yourself in the foot.
I don't think I will ever forget the look on my brothers face when he saw his new pentium d 840 throttling down to 2.8 ghz every 10 seconds. And the intel bios wouldnt let him run the fan above 50% until it got up to 67. Their goal was to keep it quiet at all costs, even if that meant taking a dual core and crippling it.
So after that the D945GTP went into the dumpster and it is happily running in a MSI P4N Sli-fi and idling at 38 and never gets above 50. That MSI motherboard let him turn off EIST.
So I'll get off my screw intel box now. I hope this has helped a little!