# AMD X2 Vs. AMD 64

## Shucklak

Just out of curiosity, has anyone had experience with Gentoo and the X2?  I'm buying a new processor soon and cannot decide whether to spend the extra bucks on the X2 or just go with the 3200.  I have heard amazing things about the 3200, and my current 2800 XP worked really well for the last 4 years.

Any suggestions would be greatly appreciated.

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## loki99

I have no first hand expereance, but using Gentoo, I'd have no doubts about getting the X2, since portage makes full use of the second core and compiling stuff is almost twice as fast.   :Shocked: 

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## Paapaa

 *Shucklak wrote:*   

> Just out of curiosity, has anyone had experience with Gentoo and the X2?  I'm buying a new processor soon and cannot decide whether to spend the extra bucks on the X2 or just go with the 3200.  I have heard amazing things about the 3200, and my current 2800 XP worked really well for the last 4 years.
> 
> Any suggestions would be greatly appreciated.

 

I also think that a dual core is the way to go. More and more software take advantage of two cores so in the near future the speed difference could be very significant. Maybe you should wait the new AM2 socket from AMD? It will be released in a few weeks (23th May?).

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## kmare

You should certainly go for a X2... everything feels smoother under heavy cpu loads.

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## Shucklak

Does everything really compile twice as fast?? I've heard that but almost find it unfathomable.

Also I've heard heard dual cores can hinder gaming.  I'm not much of a gamer anyway but I do love to indulge in some Counter Strike Source from time to time, anyone have any experience with that?

I will def wait until the AM2's are released but it will depend on the bank as to whether or not I will get one.

Thanks

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## thepustule

Dual cores hinder gaming only if the speed is slower than the single core you're comparing too.  Most games only really use one CPU, so the speed needs to be the same to keep the game speed the same.

However, any normal well-used Gentoo system has a PILE of processes running simultaneously.  Even if these programs aren't SMP-aware, as long as the kernel is, you'll get a speedup because the kernel hands processes to the different CPUs according to load.

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## stobbsm

Threading should be greatly improved with a dual core, shouldn't it?

That's the impression I get, as more threads could be open at once.

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## Shucklak

So theoritically a single 2.2 Ghz processor will play a game slightly faster than a dual 2.0 Ghz machine, both AMD socket 939's and both 64-bit? 

(I know this really means nothing because overclocking a dual 2.0 Ghz processor to 2.2 Ghz is probably not a big deal)

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## stobbsm

I know if your using cedega, it will make use of dual core (to a point) as it requires ntpl support.

Native linux games....probably depends on the game.

ps.  I'm pretty sure Wine uses threading as well.

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## Shucklak

Actually I probably should have mentioned that I will dual boot with XP.  I have tried countless times to install Windows games in Linux and it has been nothing but a hassle, so its easier to just install another hard drive with XP.  So I guess my question is how will games compare in Windows with a dual vs. a single?

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## stobbsm

Most games arn't written for dual-core.  In fact, most things in XP arn't written for dual core.

From what I understand, SP2 just gave XP the ability to fully use both cores, instead of one core at a time.

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## Mad Merlin

X2s are *fantastic*, worth every penny. I have the 4200+ and I love it. 

For example, I was playing Doom 3 and pegging the other core at 100% with some other stuff at the same time, and Doom 3 didn't slow down at all. Not to mention that compiles really are *significantly* faster, because they're embarallel (trivial to parallelize).

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## Shucklak

How about a Pentium D vs. the X2 in terms of performance, they are considerably less expensive.

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## pigeon768

 *Shucklak wrote:*   

> Does everything really compile twice as fast?? I've heard that but almost find it unfathomable.

  It's ... almost true. The majority of packages can compile two files at a time with MAKE_OPTS="-j2" (or is it MAKEOPTS? I don't remember) but not all packages. Packages that can accept MAKE_OPTS="-j2" will do the 'make' cycle virtually twice as fast. Certain areas such as the final linking won't be twice as a fast, but the rest of it will. The ./configure and any time spent unzipping files, moving files, etc etc will still only utilizing one CPU.  *Shcucklak wrote:*   

> Also I've heard heard dual cores can hinder gaming.  I'm not much of a gamer anyway but I do love to indulge in some Counter Strike Source from time to time, anyone have any experience with that?

   :Shocked:  Anyone who says dual core/CPU's hinder gaming has never played on a dualy rig. Having two CPU's does not slow anything down. The entire computing experience on a dualy rig is sooo much smoother, and that includes gaming.

Games will not utilize the second core to its full potential; however, the rest of your system will. Counter-strike will only use one core, but it will use every single bit of it; the kernel will unload the rest of the processes/threads on your system to the second core, allowing your game to completely dominate whichever core it happens to be running on. This might not seem like much, because an idle system is .. pretty idle, but the second core makes a huge difference in killing off spikes of poor performance. Every time a process needs a file from the hard disk, a single cpu will momentarily freeze while it is waiting for the hard disk to seek/read/send the data; on a dual core system, having one core freeze up won't freeze your game because the second core doesn't care about the other. Honestly though, you won't notice it until after you've seen the light and then gone back to the dark, but once you do, you'll be hooked.

I don't know about Pentium D's. I've heard certain models overclock extremely well, and if overclocking is your thing then go for it, but I've had very little experience with Intel over the past several years. Personally, I'm sticking with AMD until someone shows me different.

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## karr

I've played around with a X2 4400, and it performed well, although that's compared to the Pentium4 that I usually use an not a 3800.

Here is an older review of the amd x2 vs pentium D back in the 800 series:

http://reviews.cnet.com/4520-10442_7-6389077-8.html?tag=lnav

I don't know what the difference on the new 900 series is.

The price numbers are a little off now, but play around with the various comparisons. Regardless of whether or not you get an AM2, the old 939's should get cheaper once the AM2's are out. If you do go with the older Dual cores go with AMD. Intel and AMD are both doing major releases between now and the beginning of June, so it could be a whole new story after that. Whether you buy new or old, don' t buy until after those releases.

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## Genone

 *Shucklak wrote:*   

> How about a Pentium D vs. the X2 in terms of performance, they are considerably less expensive.

 

Pentium D == Pentium 4 == crap

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## tkdfighter

 *Mad Merlin wrote:*   

> X2s are *fantastic*, worth every penny. I have the 4200+ and I love it. 

 

++

I got a 165 and it's soooo nice!

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## Shucklak

Thanks Karr, the cnet review was most helpful.

This might be a dumb question, but how is it that a Pentium D @ 2.8 Ghz does not run as well as an X2 @ 2.0 Ghz?  Both chips are CISC correct?

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## karr

Several factors affect the performance, especially in the dual core chips. I honestly don't remember all of the specifics, but amd's have better memory controller on the chip, and at the start of the Pentium 4 line Intel begin making changes to the chip(I think it was the floating point math unit) to allow faster clock speeds while decreasing the amount of performance per clock cycle. This is what happens when the marketing department asks for faster clock speeds regardless of the effect on performance. Also the Dual core capabiities of the Pentium D are not as great as those of the X2. On raw performance numbers the X2 literally doubles the number of operations per second. The intel chips don't. There is a good article somewhere on the web with the early benchmarks of the two chips that describes the differences in how each dual core chip is built, and as a result why AMD's get better performance. If I come across it, I will post a link.

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## paulisdead

actually the problem with the p4 is the pipeline depth, i think the latest cores are up to over 30 stages in the pipeline now, whereas an A64/X2 was around about a dozen stages.  In order for an instruction to be completed it has to make it all the way through the pipeline, so shorter pipelines do more work than deeper ones, provided there aren't other limitations to the architecture.  

I might consider waiting for Intel's Conroe core to hit, since that should be coming any month now.  It'll be a shorter pipeline chip, so run at lower clocks, and is related to the pentium M so power consumption and heat should be low.  AM2 from AMD is only looking at about a 5% at best increase in performance over current 939 chips, since memory latency matters way more on the A64 than bandwidth.  In fact some benchmarks even showed AM2 chips getting beaten by 939 chips of equal clock speed just running low latency ddr400 ram.  The newer DDR2 tends to have insanely high latencies, which doesn't play as well with the onboard memory controller.  A lot of previews of the conroe core are showing it outperforming the X2s.

If you're doing the here and now, the X2 would be the way to go over the pentium D.  The gaming performance amd has over the P4 can be huge if you hit CPU limitations in games, like on a SLI setup.  Compile times are great, and generally about twice as fast, but a few ebuilds force the compile to be a single thread.  Xvid encodes in DVDrip are about twice as fast, and DVDshrink through wine even uses the second core on my X2.

Some games are also starting to take advantage of the second core/cpu now.  I don't know if the latest linux patch had, but I know the windows quake4 gets a performance boost on dual core machines.  There's a handful of other games that can take advantage of dual core, but I can't think of anymore right now.  Dual core wouldn't be much benefit to very many games right now (unless you like to leave tasks running in the background while gaming), but it will start to be more important down the road.  I know ut2007 will be multithreaded.

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## loki99

I just read in the newspaper today that amd announced at the "Spring Processor Forum", that the new amd-X2 will use less watt than th 939's. 65 watt instead of 89 watt. 

The new 3800+ should use only 35 watt.   :Shocked: 

Sounds good to me!   :Very Happy: 

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## System_Failure

<<has an X2 4400

MAKEOPTS=-j3 is my setup(#ofcpus+1) and ...:cleans himself:. it's a dream for emerging and just plan compiling for that matter. make sure to build SMP in... works great for games, can generally emerge and game at the same time with minimal effect(unless it's something big like kde, firefox(notbin), etc)... as far as intel vs AMD any comment i would make would sound to fanboi-ish so... yeah... guess what i would say   :Laughing:   ... if i think of anything else i'll post again   :Wink: 

my 2 cents,

-SF

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## paulisdead

 *loki99 wrote:*   

> I just read in the newspaper today that amd announced at the "Spring Processor Forum", that the new amd-X2 will use less watt than th 939's. 65 watt instead of 89 watt. 
> 
> The new 3800+ should use only 35 watt.  
> 
> Sounds good to me!  

 

I'm pretty sure that would have been the K8L that you read about, and not the AM2 chips about to debut.  The K8L will offer huge gains in sse/sse2/sse3 performance, and supposedly double the floating point performance.  It's supposed to be able to do quad core, and have a shared L3 cache between the cores (probably Zram).  It might be able to support DDR2 and DDR3, depending on what happens when the jedec specs are nailed down, and whether they're slot compatible whether you need a new mobo.  Thing is K8L is a ways off, the first AM2 chips will still be 90nm.  I haven't checked the roadmap exactly, but I'd say at least 6 months to a year till we see K8L on the desktop, since the opteron lineup will probably be the first to get updated.

If I were buying right now I'd seriously look at the conroe core and wait just a bit longer, since K8L seems a bit too far off.  And I'm no fan boy, I run an X2 chip in my desktop, and a 3200 A64 in my fileserver.  I just believe Intel will win this round and be ahead at least until the K8L comes out.

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## Genone

 *paulisdead wrote:*   

>  *loki99 wrote:*   I just read in the newspaper today that amd announced at the "Spring Processor Forum", that the new amd-X2 will use less watt than th 939's. 65 watt instead of 89 watt. 
> 
> The new 3800+ should use only 35 watt.  
> 
> Sounds good to me!   
> ...

 

Haven't heard about that K8L thing, he's just talking about the new EE line for the Athlon64 (they already offer it for the Opterons).

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## Ast0r

 *System_Failure wrote:*   

> can generally emerge and game at the same time with minimal effect(unless it's something big like kde, firefox(notbin), etc).

 

You should get an X2, but not for this reason. The same thing can be accomplished with PORTAGE_NICENESS=19 (or whatever you feel is an appropriate niceness) in make.conf.

I was emerging OpenOffice 2.0.2 and playing UT2004 last night with no noticable frame-rate drop on a single processor (well, Hyper-Threaded P4).

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## loki99

 *Genone wrote:*   

>  *paulisdead wrote:*    *loki99 wrote:*   I just read in the newspaper today that amd announced at the "Spring Processor Forum", that the new amd-X2 will use less watt than th 939's. 65 watt instead of 89 watt. 
> 
> The new 3800+ should use only 35 watt.  
> 
> Sounds good to me!   
> ...

 

Seems like you are  right Genone. I found another article about it, that is a little more detailed about it.

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## Algenon

I am considering replacing the AMD64 3500 on my motherboard at the moment with an AMD64 X2 4800.  Is it as easy as swappin the CPU and setting MAKEOPTS=-j3, rebooting, and recompiling only those packages that I need to take advantage of the dual core?

Algenon.

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## Shucklak

I don't know but I am very interested. If you successfully pull that off please post how you did it.

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## Mad Merlin

Yes, it should be as simple as that, assuming that you're not trying to change from x86 to amd64 (or visa versa) at the same time, that's definitely not possible without a reinstall.

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