I would say that the X1400 performs a tad better. They are pretty equivelent though. Following are some reviews with 3DMark 05 scores. I'm not a huge fan of synthetic benches but for this purpose it works.
Sony VAIO FE590:http://www.notebookreview.com/defaul...GHz+%2D+15%2E4
3Dmark 05 score of 1,714. 2.0 GHz Duo and 2gb ram (upgraded).
3Dmark 05 score of 1,655. 1.66 GHz Duo, 1gb ram, and 128mb X1400. It scores lower than the FE but Duo on 5672 is only 1.66 compared to 2.0 of FE.
A notebook closer in spec to the Sony FE is probably the Lenovo ThinkPad T60:http://www.notebookreview.com/defaul...0+2+GHz+%2D+15
3DMark 05 score of 2092. 2.0 GHz Duo, 1gb ram, and 128mb X1400.
Hope this helps!
edit: I would not call this low-end either, these solutions are more mid-end.