Yes, upgrading the RAM voids the warranty. But you can always stick the original RAM back in, if you need service.
Based on previous reports, the HP EX470/EX475 has a Sempron 3400+ running @ 1.8GHz. I don't know what version. There are several different versions of the Sempron 3400+ @ 1.8GHz --- there are desktop (65w) and notebook (25w) versions for Socket 754, as well as notebook version (25w) for Socket S1. As far as I can tell, there are no AM2 versions of the Sempron mobile, so if the HP has a AM2 socket, then it is using the desktop CPU, which we could probably replace with a faster processor.
If I had to guess, I'd say the HP probably has the "Manillia" version of the Sempron 3400+ for the AM2 socket, part # SDD3400IAA3CN.
This chip uses 1.20/1.24v and is rated at 35w. To be certain, someone needs to open up their HP, take the heatsink off the chip, and report the CPU part number.
If my guess is correct, then we
might be able to replace it with an
Athlon 64 LE-1620. Whether it would run at the full 2.4GHz or just 1.8GHz is an unknown.
What do you need a faster CPU before? The answer -- media streaming. Re-encoding high-definition content on the fly is processor intensive, and the Sempron 3400+ is no speed demon.
Here's a comparison of modern CPUs vs. the Sempron 3400+.
