As shown on our Pentium-MMX
page, the Intel Pentium-150MMX CPU in your Compaq Presario 1610 may
only be reliably upgraded to the 166MHz version, due to its core voltage
of 2.2V. Doubling your speed (up to 300MHz) with a faster, low-voltage
(1.8-2V) model may be an option, but you risk burning out your new chip.
As for your Toshiba 4000 (pdf), the
fastest Pentium-II that would fit into
your mobile module CPU connector would run at 300MHz, only a 25%
increase in speed. For any significant increase in speed, you
will be looking at a new
notebook.
This discussion is a bit academic anyway, as boxed mobile CPU's are
notoriously difficult to find and purchase-- especially the discontinued
models you are looking for. Your best bet would be to try looking around
at eBay!
A memory
upgrade
would be a better option to see a performance increase in your notebooks.