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				October 20th, 2011, 06:33 PM
			
			
			
		  
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				Corporal 
				
				
				
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				Re: 64x version of Dominions?
	
			 
             
			
		
		
		
		
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				64bit doesn't add one bit of speed unless you're doing 64bit arithmetic.  In general it will actually cost you a bit of speed as 64 bit code is bigger than 32 bit code. 
			
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 Yes!  That's so true, if you are reading your 64-bit words over an 8-bit bus.  
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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				October 21st, 2011, 04:54 PM
			
			
			
		  
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				First Lieutenant 
				
				
				
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				Re: 64x version of Dominions?
			 
             
			
		
		
		
		
	Quote: 
	
	
		
			
				
					Originally Posted by  Deathblob
					 
				 
				
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				64bit doesn't add one bit of speed unless you're doing 64bit arithmetic.  In general it will actually cost you a bit of speed as 64 bit code is bigger than 32 bit code. 
			
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 Yes!  That's so true, if you are reading your 64-bit words over an 8-bit bus.  
			
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 The memory bus is at least 64 bits, that's not a problem.
 
The problem is 64 bit code is simply bigger than 32 bit code--fewer lines of code fit into the on-chip caches, you end up with more read cycles to memory.  
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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				October 21st, 2011, 10:36 PM
			
			
			
		  
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				Corporal 
				
				
				
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					Join Date: May 2011 
					
					
					
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				Re: 64x version of Dominions?
			 
             
			
		
		
		
		
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				
	Quote: 
	
	
		
			
				
					Originally Posted by  Deathblob
					 
				 
				
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				64bit doesn't add one bit of speed unless you're doing 64bit arithmetic.  In general it will actually cost you a bit of speed as 64 bit code is bigger than 32 bit code. 
			
		 | 
	 
	 
 Yes!  That's so true, if you are reading your 64-bit words over an 8-bit bus.  
			
		 | 
	 
	 
 The memory bus is at least 64 bits, that's not a problem.
 
The problem is 64 bit code is simply bigger than 32 bit code--fewer lines of code fit into the on-chip caches, you end up with more read cycles to memory.  
			
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 Well, I thought those reads should be twice as fast, so I didn't believe you, and went googling.
 http://www.osnews.com/story/5768/Are...naries_/page1/
It's a bit old, and Sparc of all things.  But looks like you are right.   
64bit had ~+20% bigger binaries, ~-10% slower execution.  
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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				October 22nd, 2011, 11:58 AM
			
			
			
		  
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				First Lieutenant 
				
				
				
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					Join Date: Nov 2006 
					
					
					
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				Re: 64x version of Dominions?
			 
             
			
		
		
		
		
	Quote: 
	
	
		
			
				
					Originally Posted by  Deathblob
					 
				 
				
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				
	Quote: 
	
	
		
			
				
					Originally Posted by  Deathblob
					 
				 
				 
Yes!  That's so true, if you are reading your 64-bit words over an 8-bit bus. 
			
		 | 
	 
	 
 The memory bus is at least 64 bits, that's not a problem.
 
The problem is 64 bit code is simply bigger than 32 bit code--fewer lines of code fit into the on-chip caches, you end up with more read cycles to memory.  
			
		 | 
	 
	 
 Well, I thought those reads should be twice as fast, so I didn't believe you, and went googling.
 http://www.osnews.com/story/5768/Are...naries_/page1/
It's a bit old, and Sparc of all things.  But looks like you are right.   
64bit had ~+20% bigger binaries, ~-10% slower execution.  
			
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 The 64bit processor reads everything faster, whether the executable is 32bit or 64bit.  
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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				October 24th, 2011, 04:52 PM
			
			
			
		  
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				Second Lieutenant 
				
				
				
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					Join Date: Aug 2010 
					
					
					
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				Re: 64x version of Dominions?
			 
             
			
		
		
		
		
	Quote: 
	
	
		
			
				
					Originally Posted by  Loren
					 
				 
				The problem is 64 bit code is simply bigger than 32 bit code--fewer lines of code fit into the on-chip caches, you end up with more read cycles to memory. 
			
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 How long does it take for the size of "on-chip cache" to double on average PC?  
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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