Hi Guys,
I often have to process very large data files, perhaps 30Mbytes in x,y 32 bit straight BINARY format and I have always used Fortran and gnuplot in a Windows box of some sort.
I am getting this week a new windows box with a couple of 8 core Opterons, 32 GB RAM, some 6GB/s SAS RAID 0 15k rpm drives and a 512 core GTX580 CUDA/GPU video card.
Have you considered (simply!) recompiling a "fast/big" gnuplot to 64 bit Win 7 and letting it read binary files of say 1E7 x,y data points as fast as possible using CPU/GPU/CUDA cores?
Multi cores is becoming the name of the game and a few of us in the World just have to look at very big data sets.
Of course, looking at the BIG sets lets us look at the minutiae subsequently.  I like you set xrange[ ... ] apparently only working in RAM and not re-reading the whole data set out of disk in version 4.4!
I should add that whilst I do much Fortran programming and modeling in the simplest/fastest sense, I do not do GUI's in the FTN code: takes too much effort and time, hence gnuplot to simply look at the results! 

Dr Peter Leigh-Jones
Principal Engineer

Invetech Pty Ltd
Private Bag 44
495 Blackburn Road
Mount Waverley Vic 3149
Phone: xx61 3 9211 7780
Mobile: 0429 180 317
Fax: xx61 3 9211 7702
E-mail: plj@invetech.com.au
Web: http:\\www.invetech.com.au

IMPORTANT - This message, including any attachments, contains confidential and or proprietary information intended only for the addressee.  Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law.

If you are not the intended recipient, please notify the sender immediately by replying to this e-mail and delete the message and its attachments, if any, from your system.

If you have any questions about this e-mail please notify the sender immediately.
Before opening or using any attachments, check them for viruses and defects.  Our liability is limited to resupplying any affected attachments.