I have an 8470p with a 3320M at the moment.
Apparently this laptop's compatible with some hyperthreaded quad cores (3740QM, 3720QM, 3630QM, 3610QM).
Is this true? If so, are there any technicalities I should be aware of?
Ta in advance!
Firstly, upgrading a laptop cpu is usually terrible. Its hard to find a good cpu to put in there and the the process is tedious and bitchy. Then there comes the problem of thermals. The I5 natively in that model is a 35 watt cpu, all the I7's you linked are 45 watt. It may work, but its definitely going to get hotter. You actually are lucky enough to have a socketed cpu, which is rare for mobile parts. So its not impossible, but sourcing a good cpu may be difficult and the thermals are going to change.
Flip it over, unlock the bottom plate, slide it off, six captive screws. The upgrade procedure is a doddle with this machine. There's usually a few of the CPUs I mentioned in the OP floating around ebay.
The 3320M in it survived an hour of p95 without going over 70 degrees, so it'd probably be a bit toasty but I'm happy to make that sacrifice - it's rarely under full load in any situations where it wouldn't be acceptable. People seem to have gotten away with worse in 2570ps (link) I guess.
The most important things to try to get your hands on if you want to install a new CPU different from the one that's already in are:
Am I sure the BIOS is compatible with the CPU I'm going to install?
The socket can accept higher TPD CPUs?
Thermals are already enough good that the new CPU will not throttle every time I'm trying to make it work slightly harder?
This laptop appears to have been previously offered with some of the CPUs I mentioned as standard?
Links
If it's cheap, do it. I did a handful of laptop upgrades like that for myself and co-workers.
Upgraded my old single core Athlon TF-20 to a Turion dual core TL-56.
Single core AMD v120 to a Phenom II P920 quad core.
Celeron something to an i3 2310m
All worked great. A little hot, but it worked.
I was gonna do another one going from an i7 720qm to an i7 920xm, but the price killed that idea. So, again, if it's cheap, do it.