DDR3-RAM 1866MHz or higher?

Hi I just wanted to know if the diffrence between a 1866mhz memory to a 2133 or a 2400 is noticable because If I am gonna buy  a sabertooth series mobo it only supports 1866mhz memory and I am not sure if I should get another mobo that is cheaper or around the same with better memory supports...

Thanks  

Bit of a hard call for me to suggest anything here.

I'm using some Dominator Platinum 1600mhz C9 ram and things are running great, but I have been wondering this myself.  I would like to try faster ram.

As far as motherboards go which platform?  AMD or Intel?

Intel I am not sure yet but either the 3770K or the 3820 so I still have to decide if 2011 or 1155 but I have no Idea which one to buy and which mobo etc...

my budget is about 1200$ (1400 swissfranks but parts are more expensive here ) but I don't have to buy a case anymore and I do have a GPU aswell...  

ok, I've got 3770k it's pretty good.  Have a look at the Z77-V Pro and Deluxe as far as 1155, and check out some of the other offerings from Gigabyte and MSI.

The V-Pro is cheaper than the Sabertooth and has more features, better power phase design and comes with a Mini Wi-Fi card.

As for 2011 I haven't looked into them much.  Where the money is concerned with the Sabertooth is probably in the Armor thing they got going on with the 1155.  Apparently good boards but doesn't pack some of the features that the other boards have.

Sabertooth 8+4+2 Power Phase

Asus Z77-V Pro 12+4+2 Power phase, Single Band 2.5ghz Wi-Fi

Asus Z77-V Deluxe 16+4+2 Power Phase Dual Band 5ghz Wi-Fi

Both Pro and Deluxe support up to 2600mhz Memory (O.C) whether it really will reach that or not who knows but 2133mhz will work fine.

And then there's this pricey but awesome thing.

http://www.asus.co.nz/Motherboards/Intel_Socket_1155/MAXIMUS_V_FORMULA/

Just go through and compare the boards in relativity to the sabertooth paying attention to power phase design and any additional features that may be of convenience to you.  And from that you should be able to pick something nice :)