diff --git a/OpenCL/inc_types.cl b/OpenCL/inc_types.cl
index 591627eb8..752acd63c 100644
--- a/OpenCL/inc_types.cl
+++ b/OpenCL/inc_types.cl
@@ -1318,7 +1318,7 @@ typedef struct
 
 typedef struct
 {
-  u32 cmds[0x100];
+  u32 cmds[32];
 
 } kernel_rule_t;
 
diff --git a/docs/changes.txt b/docs/changes.txt
index 4ce4072bf..d828a6045 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -11,6 +11,7 @@
 - Added docs/credits.txt
 - Added docs/team.txt
 - Allow words of length > 32 in wordlists for -a 0 for slow hashes if no rules are in use or a : rule is in the rulefile
+- Reduce max. number of allowed function calls per rule from 256 to 32 to save GPU memory
 
 ##
 ## Algorithms
diff --git a/include/types.h b/include/types.h
index a289c0a3c..826f3b8fc 100644
--- a/include/types.h
+++ b/include/types.h
@@ -680,13 +680,13 @@ typedef struct
 {
   u32  len;
 
-  char buf[0x100];
+  char buf[32];
 
 } cpu_rule_t;
 
 typedef struct
 {
-  u32  cmds[0x100];
+  u32  cmds[32];
 
 } kernel_rule_t;
 
@@ -1034,7 +1034,7 @@ typedef struct
 
 } hc_global_data_t;
 
-#define RULES_MAX   256
+#define RULES_MAX   32
 #define PW_DICTMAX  31
 #define PW_DICTMAX1 (PW_DICTMAX + 1)
 
diff --git a/src/rp_cpu.c b/src/rp_cpu.c
index be1466ccd..335de121f 100644
--- a/src/rp_cpu.c
+++ b/src/rp_cpu.c
@@ -172,7 +172,7 @@ static int conv_itoc (const u8 c)
 #define SET_NAME(rule,val) (rule)->cmds[rule_cnt]  = ((val) & 0xff) <<  0
 #define SET_P0(rule,val)   INCR_POS; (rule)->cmds[rule_cnt] |= ((val) & 0xff) <<  8
 #define SET_P1(rule,val)   INCR_POS; (rule)->cmds[rule_cnt] |= ((val) & 0xff) << 16
-#define MAX_KERNEL_RULES   255
+#define MAX_KERNEL_RULES   31
 #define GET_NAME(rule)     rule_cmd = (((rule)->cmds[rule_cnt] >>  0) & 0xff)
 #define GET_P0(rule)       INCR_POS; rule_buf[rule_pos] = (((rule)->cmds[rule_cnt] >>  8) & 0xff)
 #define GET_P1(rule)       INCR_POS; rule_buf[rule_pos] = (((rule)->cmds[rule_cnt] >> 16) & 0xff)