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AM2 CPUs

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December 25, 2006 1:05:43 PM

I am interested in purchasing a new CPU and have decided to go with the AM2. Can someone please explain the pros and cons of the different wattages listed for the same model CPU. Some are at 89w, 65w, and 35w. Are there performance differences? or is it just energy consumption? Thanks for your help.

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December 25, 2006 5:46:36 PM

Quote:
I am interested in purchasing a new CPU and have decided to go with the AM2. Can someone please explain the pros and cons of the different wattages listed for the same model CPU. Some are at 89w, 65w, and 35w. Are there performance differences? or is it just energy consumption? Thanks for your help.


The wattages you are quoting are TDP spec values, they represent Thermal Design Power. This is not the power that the CPU requires to run, the actual running power is usually lower.

TDP is a specification that states how much power your cooling solution must be able to dissipate under the highest load/worst case condition. AMD defines this as the absolute maximum.

In general, the lower the TDP value the cooler the processor will be when under maximum load. This is important because for setups, such as home theater PCs, a hot or cool running CPU will require a noisy or quiet fan.

Also, please research around the reviews when AM2 CPUs were released, if you are looking to get the best performance out of an AM2 CPU setup you need high quality RAM.

JackAnd a 90nm chip...not 65nm. :wink:
December 25, 2006 9:04:38 PM

:roll: any reasons for this?! If that is a straight die shrink, why are all reviews showing decreased performance in some cases?!!!!
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December 25, 2006 9:11:04 PM

Quote:
:roll: any reasons for this?! If that is a straight die shrink, why are all reviews showing decreased performance in some cases?!!!!


It's been said time and again, but the time it takes for the CPU to access the L2 cache nearly doubles with the 65 nanometer AMD chips.
December 25, 2006 9:20:48 PM

Quote:
:roll: any reasons for this?! If that is a straight die shrink, why are all reviews showing decreased performance in some cases?!!!!


It's been said time and again, but the time it takes for the CPU to access the L2 cache nearly doubles with the 65 nanometer AMD chips.
heh, looks like I missed this! :oops: 
December 25, 2006 9:30:08 PM

YOU FOOL! Just kidding. bigbri2, Be sure to get an X2, by the way.
December 25, 2006 9:31:33 PM

Quote:
:roll: any reasons for this?! If that is a straight die shrink, why are all reviews showing decreased performance in some cases?!!!!


It's been said time and again, but the time it takes for the CPU to access the L2 cache nearly doubles with the 65 nanometer AMD chips.
heh, looks like I missed this! :oops: 

Nah, don't be ashamed. If you don't know it means you have a better chance of having a life. :) 

Or you're sucked deeply into WoW or something. :p 
December 26, 2006 1:07:39 AM

It's not even "subtract 200." It's nonexistent in some benchmarks and barely noticeable in others. If heat and energy are important to you, a 65nm chip would be better.
December 26, 2006 8:31:58 AM

Thanks for your reply. I'm looking at Corsair memory, XMS2 1GB 240-Pin DDR2 SDRAM 800 CM2X1024-6400. I've used this brand before and have had no problems with it. It also appears on the manufacturer's site as approved ram. It will be for a GA-M57SLI-S4.
December 26, 2006 11:42:40 AM

Quote:
:roll: any reasons for this?! If that is a straight die shrink, why are all reviews showing decreased performance in some cases?!!!!


It's been said time and again, but the time it takes for the CPU to access the L2 cache nearly doubles with the 65 nanometer AMD chips.
heh, looks like I missed this! :oops: 

Nah, don't be ashamed. If you don't know it means you have a better chance of having a life. :) 

Or you're sucked deeply into WoW or something. :p 
This was something not to be missed, BTW, do you happen to know why it takes 2x to get the L2 data?!
December 26, 2006 1:54:46 PM

Quote:
BTW, do you happen to know why it takes 2x to get the L2 data?!

Here's a link to the AnandTech article: AMD's 65nm Preview Part 2

The excerpt below is from the third page of this article:
Quote:
Updated: AMD has given us the official confirmation that L2 cache latencies have increased, and that it purposefully did so in order to allow for the possibility of moving to larger cache sizes in future parts. AMD stressed that this wasn't a pre-announcement of larger cache parts to come, but rather a preparation should the need be there to move to a vastly larger L2. Thankfully the performance delta isn't huge, at least in the benchmarks that we saw, so AMD's decision isn't too painful - especially as it comes with the benefit of a cooler running core that draws less power; ideally we'd like the best of all worlds but we'll take what we can get. Note that none of AMD's current roadmaps show any larger L2 parts (other than the usual 2x1MB offerings), which tells us one of two things: either AMD has some larger L2 parts that it's planning on releasing or AMD is being completely honest with the public in saying that the larger L2 parts will only be released if necessary.


-john
December 26, 2006 3:56:57 PM

Quote:
It's not even "subtract 200." It's nonexistent in some benchmarks and barely noticeable in others. If heat and energy are important to you, a 65nm chip would be better.


It actually can get pretty bad compared to 90nm depending on the benchmark:
http://www.firingsquad.com/hardware/amd_athlon_64_4800_...

Personally, I'd take an extra 20W over a 1 - 10% clock for clock deficit.
December 26, 2006 6:22:53 PM

Quote:
Thanks for your reply. I'm looking at Corsair memory, XMS2 1GB 240-Pin DDR2 SDRAM 800 CM2X1024-6400. I've used this brand before and have had no problems with it. It also appears on the manufacturer's site as approved ram. It will be for a GA-M57SLI-S4.



I'll reply to that (since by virtue of the fact that none of the above posters are interested in helping you with your decision, but rather going on a rant and creating as much negative spin as possible, as witnessed above). That would be a good choice of ram for your build.
December 26, 2006 6:30:35 PM

I say don't sweat it at all, instead start with a inexpensive 90nm chip, like the X2 4200, because for now, the cpu will *not* be decisive in system performance. Intead, for now, it's the graphics card and the hard drives that matter. And, you save money and wait for 2nd half 2007 for some nice upgrade options, including quad core. Of course any low end quad core will blow away all and every type of dual core, "extreme" included. :) 
!