All times in seconds unless otherwise noted.

Cases where Fermat wins are marked * or ** (big win).
Cases where Magma wins are marked -

Fermat seems to win big in the largest cases.

Magma file           Fermat file 
  and time             and time

zbacon    8.82-      bacon  88 
zhypb     19.7       hypbb  9.70 *
zp3n       .40       zip3n .68  
zp30      3.74       zip30  1.84 *
zp31m      .52       zip31m  .260 *
zp3pp     3.58       zip3pp  .050 **

zpb6      26.1       zipb6  6.23 **
zpbb2n     .77       zipbb2n  1.22  
zpbn2      .86-      zipbn2  1.83   
zpbou2   22.56-      zipbou2  52.4  
zpcpal     .55-      zipcpal 1.25  
zpev       .52       zipev  .57  
zpg       7.74       zipgood 3.86 *

zphern    5.90       ziphern  1.98 **    
zphyp3n  171.0       ziphyp3n  43.2 **
zpk2      8.16       zipkk3 7.81         
zpk4       .68       zipk4 0.10  **
zpkk3     7.11       zipkk3n 6.60   
zpkkln    8.28       zipkkln 6.71   
zpaln     3.31-      zippaln  8.07  
zpq5c    111.6       zipq5   52   **
zpq75n 1 hr 6 min    zipq75n   1 hr 22 min 

zthload  51.13       ziptho8o   12.58 **
vacout 10 min 32 sec vac2out  4 min 28 sec **
 
zpq7a4    4.72       zipq7a4  4.14      
zpq7 no    .25-      zipq7m  1.07    
zpq73     2.30-      zipq73  6.75            
zpq81     2.10-      zipq81n   6.22      
zptho7    39.4       ziptho7  17.33  **
zptot      .29-      ziptot   .54   
zvac      7.50       zipvac  4.24  *  
zvac5     3.44       zipvac5  .840  **   
zpvbno    7.51       zipvbno  4.11  *  

zp9load 85 min 10 sec     ziptho9  18 min 20 sec  **  
                          After loading, do &(p = 2147483629);

zth2load  801 min 35 sec  tho2tst 37 min 27 sec **


The magma command:   time b := GCD(xx,yy);