This is more of a note to self as I am constantly self-confusing myself with how much data can be loaded into a PowerPivot model.
Basically, there are two things to consider, version of office one is running and whether a SharePoint deployment option is required.
First, whether one is running a 32 or a 64 Bit version of Excel. The 32 Bit version can only address 2GB of memory which effectively limits the size of the PowerPivot workbook to about 500-700Mb. The 64 bit version used to be limited to 4Gb file size in Excel 2010 but in Excel 2013 that limitation has been removed which means that the size of the workbook is no longer limited by the software but rather by the physical configuration of one’s machine.
Unfortunately, should one plan on posting that workbook in SharePoint, the SharePoint size limitation will dictate that only up to a 2GB file can be uploaded.
Here is the link for more information: http://office.microsoft.com/en-us/excel-help/data-model-specification-and-limits-HA102837464.aspx?CTT=5&origin=HA102893837
business intelligist 
I have 64-bit Excel 2013 and I cannot open a file larger than 2GB. There error message is:
An error occurred while loading the file.
More Details:Failed to retrieve data from datafile#txt. Reason: The query cannot be completed. Either the size of the query result is larger than the maximum size of a database (2 GB), or there is not enough temporary storage space on the disk to store the query result.
From the software perspective, 64 bit version of excel will be able to handle this file, however, you still need to make sure that the hardware is there to support it as well. I just opened a 2GB Power Pivot file on my machine and this file takes up almost 3gb of RAM and there are also some temp files that are created, so you should have some disk space available as well.
Generally speaking, 64 Bit Excel running on a machine with 8GB of RAM and with 10GB of free disk space should have no problem handling 2gb Power Pivot file. My test machine has 16GB RAM and 1TB solid state hard drive, but I think it is probably an overkill for what you are trying to do.
Check out this link for more information
I get the same error with 2013 64bit version and 16GB of RAM on a 5GB file so it appears Powerpivot does have a 4GB limitation?
No limitations for 64 bit version.