Originally Posted by Krimble
I bought a Razer Mamba 5600 dpi and I LOVE it!
But the R.A.T CYBORG one looks decent also
You bought a Mamba? Nice, but I'd send it back if you still can
. In order to reduce some jitter problems they have on soft surfaces (like cloth mousepads), they've implemented some dynamic DPI scaling into their firmwares. This is some sort of acceleration and you can't turn it off either. The slower you move the mouse the more DPI is reduced automatically, which will kill your precision. You might be lucky though and find an older firmware somewhere for your Mamba 3.5G 5600 which doesn't have that.
Originally Posted by Glymbol
None, 1 is as good as any other setting
Performance-wise it probably depends on the game/engine but a higher sens will always produce more staircase-like tracking.