I don't have another PSU. What problem do you believe would be solved by that?
I don't think a dedicated DF tower would be that expensive to a general purpose tower. I'm not going for the best CPU and the best RAM, but spending more money on those at the expense of the graphics card and parts of the hard drive.
I ran into something strange about a year ago with dwarf fortress and hardware, when I bought used parts on Ebay, and put together a cheap system based on the A10-5800K CPU, and 8gb of ddr3 2133 RAM.
Then I found out that in the case of Dwarf Fortress, this got just over double the FPS of my main gaming tower, which was based on the 1100T CPU, and 8gb of ddr2 800 ram.
The 1100T system left the A10 in the dust for most other games, but in Dwarf Fortress, the A10 was king.
As is obvious, Dwarf Fortress didn't care at all about the fancy video cards in my main tower,
the CPUs have very similar single core performance, which left just one variable, the memory.
After some testing, I noticed that the advantage went away when I put slower RAM in the A10.
So I'm going to have to say that when/if you are building a system specifically for Dwarf Fortress, be very careful on saving on RAM.
What one should mostly focus on if building a computer just for dwarf fortress, is single thread performance on the CPU, and RAM speed.
Everything else is secondary.
And of course make sure the CPU properly supports the RAM:
The 1100T with ddr3 2133 didn't make any miracles, and instead, refused to run it at speeds over 1600(and even that speed is NOT officially supported)
On those CPUs you changed out.. is that a laptop you are tweaking?
that would explain the difficulty in testing other parts, like a different PSU,
as well as the crash, while the difference in power draw(25w vs 35w) is tiny for a desktop, for a laptop, that could increase heat in the system, and cause secondary problems that way.
In the case that this CPU is officially supported, that should be fine though.
And I would guess the system booted again BECAUSE you messed with the RAM,
a lot of laptops I have messed with reset their CMOS if you change the RAM.
I wouldn't count on that way to reset CMOS, but its the best explanation I can think of