diff --git a/common/const.h b/common/const.h
index bffcebc7..fe4469fa 100644
--- a/common/const.h
+++ b/common/const.h
@@ -14,9 +14,6 @@
 ****/
 #ifndef CONST_H
 #define CONST_H
-
-#include <stddef.h> // ptrdiff_t
-
 //
 // Constants shared by the engine and dlls
 // This header file included by engine files and DLL files.
@@ -724,7 +721,7 @@ enum
 };
 
 typedef int		func_t;
-typedef ptrdiff_t	string_t;
+typedef int		string_t;
 
 typedef unsigned short	word;
 
diff --git a/engine/common/lib_common.c b/engine/common/lib_common.c
index c4ff6cb1..7c4fb8aa 100644
--- a/engine/common/lib_common.c
+++ b/engine/common/lib_common.c
@@ -126,20 +126,14 @@ dll_user_t *FS_FindLibrary( const char *dllname, qboolean directpath )
 =============================================================================
 */
 
-static void COM_GenerateCommonLibraryName( const char *name, const char *ext, const char *suffix, char *out, size_t size )
+static void COM_GenerateCommonLibraryName( const char *name, const char *ext, char *out, size_t size )
 {
 #if ( XASH_WIN32 || XASH_LINUX || XASH_APPLE ) && XASH_X86
-	if( suffix )
-		Q_snprintf( out, size, "%s_%s.%s", name, suffix, ext );
-	else Q_snprintf( out, size, "%s.%s", name, ext );
+	Q_snprintf( out, size, "%s.%s", name, ext );
 #elif ( XASH_WIN32 || XASH_LINUX || XASH_APPLE )
-	if( suffix )
-		Q_snprintf( out, size, "%s_%s_%s.%s", name, Q_buildarch(), suffix, ext );
-	else Q_snprintf( out, size, "%s_%s.%s", name, Q_buildarch(), ext );
+	Q_snprintf( out, size, "%s_%s.%s", name, Q_buildarch(), ext );
 #else
-	if( suffix )
-		Q_snprintf( out, size, "%s_%s_%s_%s.%s", name, Q_buildos(), Q_buildarch(), suffix, ext );
-	else Q_snprintf( out, size, "%s_%s_%s.%s", name, Q_buildos(), Q_buildarch(), ext );
+	Q_snprintf( out, size, "%s_%s_%s.%s", name, Q_buildos(), Q_buildarch(), ext );
 #endif
 }
 
@@ -160,7 +154,7 @@ static void COM_GenerateClientLibraryPath( const char *name, char *out, size_t s
 	// we don't have any library prefixes, so we can safely append dll_path here
 	Q_snprintf( dllpath, sizeof( dllpath ), "%s/%s", GI->dll_path, name );
 
-	COM_GenerateCommonLibraryName( dllpath, OS_LIB_EXT, NULL, out, size );
+	COM_GenerateCommonLibraryName( dllpath, OS_LIB_EXT, out, size );
 #endif
 }
 
@@ -217,13 +211,7 @@ static void COM_GenerateServerLibraryPath( char *out, size_t size )
 	COM_StripExtension( dllpath );
 	COM_StripIntelSuffix( dllpath );
 
-#if XASH_ARCH_USES_ONLY_ABI2
-	COM_GenerateCommonLibraryName( dllpath, ext, NULL, out, size );
-#elif XASH_64BIT
-	COM_GenerateCommonLibraryName( dllpath, ext, "st64", out, size );
-#else
-	COM_GenerateCommonLibraryName( dllpath, ext, NULL, out, size );
-#endif
+	COM_GenerateCommonLibraryName( dllpath, ext, out, size );
 #endif
 }
 
diff --git a/engine/eiface.h b/engine/eiface.h
index 3bda3265..e18cdedb 100644
--- a/engine/eiface.h
+++ b/engine/eiface.h
@@ -125,7 +125,7 @@ typedef struct enginefuncs_s
 	void	(*pfnAngleVectors)( const float *rgflVector, float *forward, float *right, float *up );
 	edict_t*	(*pfnCreateEntity)( void );
 	void	(*pfnRemoveEntity)( edict_t* e );
-	edict_t*	(*pfnCreateNamedEntity)( string_t className );
+	edict_t*	(*pfnCreateNamedEntity)( int className );
 	void	(*pfnMakeStatic)( edict_t *ent );
 	int	(*pfnEntIsOnFloor)( edict_t *e );
 	int	(*pfnDropToFloor)( edict_t* e );
@@ -168,8 +168,8 @@ typedef struct enginefuncs_s
 	void*	(*pfnPvAllocEntPrivateData)( edict_t *pEdict, long cb );
 	void*	(*pfnPvEntPrivateData)( edict_t *pEdict );
 	void	(*pfnFreeEntPrivateData)( edict_t *pEdict );
-	const char *(*pfnSzFromIndex)( string_t iString );
-	string_t	(*pfnAllocString)( const char *szValue );
+	const char *(*pfnSzFromIndex)( int iString );
+	int	(*pfnAllocString)( const char *szValue );
 	struct entvars_s *(*pfnGetVarsOfEnt)( edict_t *pEdict );
 	edict_t*	(*pfnPEntityOfEntOffset)( int iEntOffset );
 	int	(*pfnEntOffsetOfPEntity)( const edict_t *pEdict );
diff --git a/engine/progdefs.h b/engine/progdefs.h
index fb636827..2a0e133b 100644
--- a/engine/progdefs.h
+++ b/engine/progdefs.h
@@ -85,8 +85,8 @@ typedef struct entvars_s
 	int		modelindex;
 
 	string_t		model;
-	string_t		viewmodel;	// player's viewmodel
-	string_t		weaponmodel;	// what other players see
+	int		viewmodel;	// player's viewmodel
+	int		weaponmodel;	// what other players see
 
 	vec3_t		absmin;		// BB max translated to world coord
 	vec3_t		absmax;		// BB max translated to world coord
@@ -144,7 +144,7 @@ typedef struct entvars_s
 	int		flags;
 
 	int		colormap;		// lowbyte topcolor, highbyte bottomcolor
-	string_t		team;
+	int		team;
 
 	float		max_health;
 	float		teleport_time;
diff --git a/engine/server/sv_game.c b/engine/server/sv_game.c
index f424656a..29d53549 100644
--- a/engine/server/sv_game.c
+++ b/engine/server/sv_game.c
@@ -3000,6 +3000,25 @@ static void *GAME_EXPORT pfnPvEntPrivateData( edict_t *pEdict )
 }
 
 
+#ifdef XASH_64BIT
+static struct str64_s
+{
+	size_t maxstringarray;
+	qboolean allowdup;
+	char *staticstringarray;
+	char *pstringarray;
+	char *pstringarraystatic;
+	char *pstringbase;
+	char *poldstringbase;
+	char *plast;
+	qboolean dynamic;
+	size_t maxalloc;
+	size_t numdups;
+	size_t numoverflows;
+	size_t totalalloc;
+} str64;
+#endif
+
 /*
 ==================
 SV_EmptyStringPool
@@ -3009,7 +3028,17 @@ Free strings on server stop. Reset string pointer on 64 bits
 */
 void SV_EmptyStringPool( void )
 {
+#ifdef XASH_64BIT
+	if( str64.dynamic ) // switch only after array fill (more space for multiplayer games)
+		str64.pstringbase = str64.pstringarray;
+	else
+	{
+		str64.pstringbase = str64.poldstringbase = str64.pstringarraystatic;
+		str64.plast = str64.pstringbase + 1;
+	}
+#else
 	Mem_EmptyPool( svgame.stringspool );
+#endif
 }
 
 /*
@@ -3023,8 +3052,23 @@ this helps not to lose strings that belongs to static game part
 */
 void SV_SetStringArrayMode( qboolean dynamic )
 {
+#ifdef XASH_64BIT
+	Con_Reportf( "%s(%d) %d\n", __func__, dynamic, str64.dynamic );
+
+	if( dynamic == str64.dynamic )
+		return;
+
+	str64.dynamic = dynamic;
+
+	SV_EmptyStringPool();
+#endif
 }
 
+#if XASH_AMD64 && XASH_LINUX && !XASH_ANDROID
+#define USE_MMAP
+#include <sys/mman.h>
+#endif
+
 /*
 ==================
 SV_AllocStringPool
@@ -3037,13 +3081,104 @@ this case need patched game dll with MAKE_STRING checking ptrdiff size
 */
 static void SV_AllocStringPool( void )
 {
+#ifdef XASH_64BIT
+	void *ptr = NULL;
+	string lenstr;
+
+	Con_Reportf( "%s()\n", __func__ );
+	if( Sys_GetParmFromCmdLine( "-str64alloc", lenstr ) )
+	{
+		str64.maxstringarray = Q_atoi( lenstr );
+		if( str64.maxstringarray < 1024 || str64.maxstringarray >= INT_MAX )
+			str64.maxstringarray = 65536;
+	}
+	else str64.maxstringarray = 65536;
+	if( Sys_CheckParm( "-str64dup" ) )
+		str64.allowdup = true;
+
+#ifdef USE_MMAP
+	{
+		uint flags;
+		size_t pagesize = sysconf( _SC_PAGESIZE );
+		int arrlen = (str64.maxstringarray * 2) & ~(pagesize - 1);
+		void *base = svgame.dllFuncs.pfnGameInit;
+		void *start = svgame.hInstance - arrlen;
+
+#if defined(MAP_ANON)
+		flags = MAP_ANON | MAP_PRIVATE;
+#elif defined(MAP_ANONYMOUS)
+		flags = MAP_ANONYMOUS | MAP_PRIVATE;
+#endif
+
+		while( start - base > INT_MIN )
+		{
+			void *mapptr = mmap((void*)((unsigned long)start & ~(pagesize - 1)), arrlen, PROT_READ | PROT_WRITE, flags, 0, 0 );
+			if( mapptr && mapptr != (void*)-1 && mapptr - base > INT_MIN && mapptr - base < INT_MAX )
+			{
+				ptr = mapptr;
+				break;
+			}
+			if( mapptr ) munmap( mapptr, arrlen );
+			start -= arrlen;
+		}
+
+		if( !ptr )
+		{
+			start = base;
+			while( start - base < INT_MAX )
+			{
+				void *mapptr = mmap((void*)((unsigned long)start & ~(pagesize - 1)), arrlen, PROT_READ | PROT_WRITE, flags, 0, 0 );
+				if( mapptr && mapptr != (void*)-1  && mapptr - base > INT_MIN && mapptr - base < INT_MAX )
+				{
+					ptr = mapptr;
+					break;
+				}
+				if( mapptr ) munmap( mapptr, arrlen );
+				start += arrlen;
+			}
+		}
+
+
+		if( ptr )
+		{
+			Con_Reportf( "%s: Allocated string array near the server library: %p %p\n", __func__, base, ptr );
+
+		}
+		else
+		{
+			Con_Reportf( "%s: Failed to allocate string array near the server library!\n", __func__ );
+			ptr = str64.staticstringarray = Mem_Calloc( host.mempool, str64.maxstringarray * 2 );
+		}
+	}
+#else
+	ptr = str64.staticstringarray = Mem_Calloc( host.mempool, str64.maxstringarray * 2 );
+#endif
+
+	str64.pstringarray = ptr;
+	str64.pstringarraystatic = (byte*)ptr + str64.maxstringarray;
+	str64.pstringbase = str64.poldstringbase = ptr;
+	str64.plast = (byte*)ptr + 1;
+	svgame.globals->pStringBase = ptr;
+#else
 	svgame.stringspool = Mem_AllocPool( "Server Strings" );
 	svgame.globals->pStringBase = "";
+#endif
 }
 
 static void SV_FreeStringPool( void )
 {
+#ifdef XASH_64BIT
+	Con_Reportf( "%s()\n", __func__ );
+
+#ifdef USE_MMAP
+	if( str64.pstringarray != str64.staticstringarray )
+		munmap( str64.pstringarray, (str64.maxstringarray * 2) & ~(sysconf( _SC_PAGESIZE ) - 1) );
+	else
+#endif
+		Mem_Free( str64.staticstringarray );
+#else
 	Mem_FreePool( &svgame.stringspool );
+#endif
 }
 
 /*
@@ -3114,6 +3249,9 @@ string_t GAME_EXPORT SV_AllocString( const char *szValue )
 {
 	char *newString = NULL;
 	uint len;
+#ifdef XASH_64BIT
+	int cmp;
+#endif
 
 	if( svgame.physFuncs.pfnAllocString != NULL )
 	{
@@ -3129,16 +3267,67 @@ string_t GAME_EXPORT SV_AllocString( const char *szValue )
 		return i;
 	}
 
+#ifdef XASH_64BIT
+	cmp = 1;
+
+	if( !str64.allowdup )
+	{
+		for( newString = str64.poldstringbase + 1;
+			newString < str64.plast && ( cmp = Q_strcmp( newString, szValue ) );
+			newString += Q_strlen( newString ) + 1 );
+	}
+
+	if( cmp )
+	{
+		uint len = SV_ProcessString( NULL, szValue );
+
+		if( str64.plast - str64.poldstringbase + len + 1 > str64.maxstringarray )
+		{
+			str64.plast = str64.pstringbase + 1;
+			str64.poldstringbase = str64.pstringbase;
+			str64.numoverflows++;
+		}
+
+		//MsgDev( D_NOTE, "SV_AllocString: %ld %s\n", str64.plast - svgame.globals->pStringBase, szValue );
+		SV_ProcessString( str64.plast, szValue );
+		str64.totalalloc += len;
+
+		newString = str64.plast;
+		str64.plast += len;
+	}
+	else
+	{
+		str64.numdups++;
+		//MsgDev( D_NOTE, "SV_AllocString: dup %ld %s\n", newString - svgame.globals->pStringBase, szValue );
+	}
+
+	if( newString - str64.pstringarray > str64.maxalloc )
+		str64.maxalloc = newString - str64.pstringarray;
+
+	return newString - svgame.globals->pStringBase;
+#else
 	len = SV_ProcessString( NULL, szValue );
 	newString = Mem_Malloc( svgame.stringspool, len );
 	SV_ProcessString( newString, szValue );
 
 	return newString - svgame.globals->pStringBase;
+#endif
 }
 
 void SV_PrintStr64Stats_f( void )
 {
+#ifdef XASH_64BIT
+	Con_Printf( "====================\n" );
+	Con_Printf( "64 bit string pool statistics\n" );
+	Con_Printf( "====================\n" );
+	Con_Printf( "string array size: %lu\n", str64.maxstringarray );
+	Con_Printf( "total alloc %lu\n", str64.totalalloc );
+	Con_Printf( "maximum array usage: %lu\n", str64.maxalloc );
+	Con_Printf( "overflow counter: %lu\n", str64.numoverflows );
+	Con_Printf( "dup string counter: %lu\n", str64.numdups );
+#else
 	Con_Printf( "Not implemented\n" );
+#endif
 }
 
 /*
@@ -3152,8 +3341,17 @@ string_t SV_MakeString( const char *szValue )
 {
 	if( svgame.physFuncs.pfnMakeString != NULL )
 		return svgame.physFuncs.pfnMakeString( szValue );
-
+#ifdef XASH_64BIT
+	{
+		long long ptrdiff = szValue - svgame.globals->pStringBase;
+		if( ptrdiff > INT_MAX || ptrdiff < INT_MIN )
+			return SV_AllocString(szValue);
+		else
+			return (int)ptrdiff;
+	}
+#else
 	return szValue - svgame.globals->pStringBase;
+#endif
 }
 
 /*