[Athlon 64] Socket 754 vs. Socket 939

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Twisted Metal

Twisted Metal

Anfractuous Aluminum
Jul 28, 2001
7,122
3
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Long Island, NY
Hey guys, I've been browsing around on newegg looking for parts to build a new PC... I want a 64 bit Athlon, but I don't want to pay 600+ bucks just for the processor.

First I was browsing through socket 754 processors and found the 3400+ which is 2.2 ghz and has 1 MB of L2 cache. Current cost of this processor is $295.00.

Then I looked through some socket 939 processors and found the 3500+ which is 2.2 ghz and has only 512k of L2 cache. Current cost of this processor is $339.00.

Now my question is, what is so special about the 939 that makes it worth $45 more? It is the same speed (2.2 ghz) and it has even less L2 cache than the 754. I know that the 939 is good to get because of upgradability... And I think 939 processors/motherboards have higher FSB speed (1 ghz) but I'm not too sure.

I'm trying to make a decent gaming PC, one that will run the new generation of games: Half-Life 2, Doom 3, etc... smoothly. I will definitely be getting a top of the line video card and 1 ghz of ram.

Any suggestions to help with my processor choice?

Thanks guys.
 
Chaser

Chaser

Boi BOI!!!!
Mar 16, 2004
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I've been shopping around for a Athlon 64 system as well and I have the same questions. From what i've been gathering so far, I think the 939s are better because the motherboards support dual channel ram. I also heard that the Ghz has little to do with the actual speed of the processor, and that there are many more things that come into play when trying to determine the speed. Also I thought the new AMD64s didnt have a FSB because the memory controller was integrated into the chip?? or am I just confusing myself more? lol
 
Twisted Metal

Twisted Metal

Anfractuous Aluminum
Jul 28, 2001
7,122
3
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Long Island, NY
I got an answer to my question on another message board(3dbuzz). If you are interested Chaser here is the response I got:

Socket 754 is an awesome value right now, especially if you buy the DFI NF3-250GB LanParty board. There is no better overclocker in the entire world. However, buy knowing that there is no future upgrade path for this board or chip.

Socket 939 is the future, but it does not outperform 754 by significant margins right now. It is also substantially more expensive. That ain't right. These boards to have a future, but some folks never upgrade a system after it is built. If you are such an individual get 754. Also the population of 939 boards are both scarce and expensive.

It all boils down to whether you are an upgrader or not.

As far as the bus speed is concerned either 754 or 939 can opperate with the Hypertransport bus at 5x or 1GHz. You just have to ensure that you get an NForce 3-250GB board, or a VIA K8T800 Pro. It is in the motherboard, not the CPU.

As far as the cache thing is concerned 512KB is enough to optimize Athlon 64 performance. The extra 512KB gives you a small bump, but it isn't worth much according to the benchmarks. If you take AMD's "Plus Rating" at face-value, AMD is telling us that 512KB of cache is only worth 200MHz of Pentium 4 power. The bunchmarks suggest that it is worth less than that.
Click to expand...
 
B

BinarySystem

Banned
Jun 10, 2004
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Say what? 512KB of cache worth a certain amount of clock speed? WTF?

It sounds like that person is suggesting that that's the difference in benchmark performance it will give you, but that's kind of hard to justify since the usefulness of L2 cache depends highly on what the machine language for a given program looks like. (Lots of little loops or less big loops.)
 
PsychoMoggieBagpuss

PsychoMoggieBagpuss

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Mar 6, 2000
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BinarySystem said:
Say what? 512KB of cache worth a certain amount of clock speed? WTF?

It sounds like that person is suggesting that that's the difference in benchmark performance it will give you, but that's kind of hard to justify since the usefulness of L2 cache depends highly on what the machine language for a given program looks like. (Lots of little loops or less big loops.)
Click to expand...

Just increasing the L2 cache size above a certain point does not increase real world performance.
Increasing the efficiency (via better caching algorithms) of it does though, as the usefulness of a cache all depends on whether the data you want is in there already, and how quickly it takes you to find it.
 
Dead_Hood

Dead_Hood

The Seventh Sign
Apr 24, 2001
308
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That's exactly AMD's take on the socket situation. In their eyes, having and extra 512k give similar performance to having and extra 200MHz.

There is nothing wrong with the 754 socket. Sure, it doesn't have a dual channel memory controller, but it really doesn't make a big difference in terms of actual performance. I am currently running a socket 754 3400+ on an nForce3 motherboard, and I couldn't be happier with my rig. If you buy a socket 939 board and chip, chances are that you'll want a new mobo by the time you want a new CPU anyway. With the 754 prices dropping considerably, I can't really see a reason why people wouldn't want one of these chips.
 
B

BinarySystem

Banned
Jun 10, 2004
705
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PsychoMoggieBagpuss said:
Just increasing the L2 cache size above a certain point does not increase real world performance.
Increasing the efficiency (via better caching algorithms) of it does though, as the usefulness of a cache all depends on whether the data you want is in there already, and how quickly it takes you to find it.
Click to expand...
Like I said, this depends on the machine code being used - if you are in a loop that's larger than you cache, you will see a MAJOR performance drop. Granted, not many loops are larger than 512KB, but if you had a program that had a loop larger than this, there would be significant performance gains from having more L2 cache.
 
Chaser

Chaser

Boi BOI!!!!
Mar 16, 2004
497
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0
Twisted Metal said:
I got an answer to my question on another message board(3dbuzz). If you are interested Chaser here is the response I got:
Click to expand...

Thanks for the info :tup:. I like being able to upgrade, but my current machine was built with upgrading in mind... and now i just want to buy a whole new motherboard. So I might as well go with the 754, unless the 939 price drops considerably.
 
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