电脑内存足够，网格划分不算太多，求解还老是出错

电脑内存原来是8g，后来加装了8g的内存条，网格划分的数量跟加装内存条前差不多，也就15万网格，为什么求解时老是出现下面的问题，上网查了很久，都没查到原因，求大神解救。

问题如下：

*** WARNING ***                         CP =      55.141   TIME= 21:45:50
 The Distributed Sparse Matrix Solver is currently running in the       
 out-of-core memory mode.  This memory mode may provide significantly   
 worse performance compared to the in-core memory mode, depending on    
 the amount of available system memory and I/O speed.  Please monitor   
 the solver performance to ensure that the large amount of I/O to the   
 solver files does not create a bottleneck for performance.             

 *** ERROR ***                           CP =      98.562   TIME= 21:46:41
 An input/output error has occurred while trying to open a file with    
 length = 3 GB.  Error code = 112, which translates to: 磁盘空间不足。  
                                                                        

 *** ERROR ***                           CP =      98.562   TIME= 21:46:41
 The program is unable to open file file1.DSPtri.  If the suggestions in
 the associated error messages immediately preceding and/or following   
 this error message do not help resolve the file issue, please send the 
 data leading to this operation to your technical support provider,     
 along with the I/O error code of -1 and the system error code of 0,    
 for help in determining the possible reasons as to why this file could 
 not be opened.                                                         

 *** ERROR ***                           CP =      98.562   TIME= 21:46:41
 An input/output error has occurred on the process with MPI Rank ID = 1.
  This error occurs when trying to open a file with length = 4 GB.      
 Please check to make sure there is enough free disk space in the       
 working directory (E:\zuijin\anli\_ProjectScratch\Scr5288) on machine  
 (DESKTOP-J2BGQ1T).