Dual Dell U2412 monitors w/ MacBook Air and Matrox dualhead2go dp

Hi,

According to Matrox, a new MacBook Air with a DualHead2Go (Display port edition) will only push the native resolution to these monitors at 50Hz.

The optimal resolution is 1920x1200 @ 60Hz.  Does this mean that if they receive 1920x1200 @ 50Hz, nothing will display?  Or will it just be "slow."  I'm not using this for videos/gaming/etc.; strictly productivity apps, so any kind of motion artifacts are not a big deal.

I did search the forum, but wasn't sure any previous posts applied to me.

dualhead2go:  http://www.matrox.com/graphics/en/products/gxm/dh2go/

dualhead2go MacBook Air specific info (hit Macbook Air, then "Mid 2011," then "2 displays: http://www.matrox.com/graphics/en/products/gxm/mac/choice/

Dell Monitor specs:  http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&cs=19&sku=320-2676&baynote_bnrank=1&baynote_irrank=0&~ck=baynoteSearch

Thank you!