The "Verifying last 288 blocks at level 3" phase takes much longer in RC3 than it did in RC1. RC1 was about 3-4 minutes. I've now started RC3 twice, and it took 13 and 18 minutes. This is about as bad as 0.9.3, which sometimes took over 20 minutes.
OS: Windows XP 32-bit
Nothing changed between rc1 and rc3 related to that. Are you sure it's not a disk cache issue or a change in -dbcache between the two attempts (a lower dbcache value is actually faster, as the expensive part of the validation is only done until the dbcache fills up; with a lower value it effectively doesn't verify as much).
Hm. I shut down a background program (data logger for a USB thermometer) and that solved the problem. Weird. The data logger was using a bit of CPU, but I don't see how it could have slowed Bitcoin Core down by a factor of 5. I wonder if it's related to the fact that I keep the Bitcoin data directory on an external USB drive. Maybe the data logger was spamming the USB controller or something?
You can exactly control how much work the startup check will do using -checkblocks=X and -checkblocksverify=X.
Leveldb generates quite a lot of I/O traffic during the check. If you add more devices that consume bandwidth on the bus it's thus going to be slower.
After some more testing I actually think the slowness was due to Windows being low on memory. I got the slow startup also while the USB thermometer program wasn't running, but after killing off a bunch of Google Chrome processes to get the memory usage down, Bitcoin started quickly again. I wonder if I never tested RC1 with Chrome being quite as bloated, or if something is different in RC3...