Ninja Plus Rev. B fan question

[Lt_Dan]

Hey,

I have my Ninja for some time, i recently added the stabilizer 775( which the mods help me install), and it is connected to a Zalman Fanmate2.

I was wondering about the fan that came with the ninja, it says it's a sleeve bearing. but what model is it (when you check other Scythe fans)?

also, currently it runs at ~750rpm, it isn't smooth. and it has a lot of variations - it jumps around 740-760rpm all the time.
so does my s-flex(1200rpm) that runs at ~710rpm.

- another fan of mine runs at 700rpm and is pretty steady - (Noctua writes it has an SCD2...).

ps. what is its starting voltage and it's min rpm before it stalls?

hope you can help with sorting this out,
Thanks,
Dan.