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October 20th, 2011, 06:33 PM
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Corporal
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Join Date: May 2011
Posts: 103
Thanks: 17
Thanked 24 Times in 17 Posts
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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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Join Date: Nov 2006
Posts: 739
Thanks: 1
Thanked 8 Times in 8 Posts
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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
Posts: 103
Thanks: 17
Thanked 24 Times in 17 Posts
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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.
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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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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
Posts: 739
Thanks: 1
Thanked 8 Times in 8 Posts
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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.
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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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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
Posts: 546
Thanks: 100
Thanked 10 Times in 8 Posts
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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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