AMD64 / Athlon X2 Opinions

Vlad · Posted: Wed Sep 28, 2005 2:21 am Post subject: AMD64 / Athlon X2 Opinions

Hi everyone,

In a few days I'll start building my first 64-bit system. As I await the arrival of my parts from newegg, I've been perusing the forums checking out the state of AMD64. I was wondering if anyone could supply me with some feedback on their impression of the performance of stability of Gentoo on AMD64, particularly in regards to the new Athlon X2. I am by no means a Gentoo or linux novice, having several systems currently running Gentoo. I anticipate my installation to have at least some pitfalls, as this is all fairly new hardware, but I'd greatly appreciate any pearls of wisdom anyone can offer on their experience with the migration from 32 to 64 bits.

What do you think of the performance difference between 32 and 64? How difficult was installation? Has anyone had much success with Gentoo on the X2s? Are the problems with nvidia cards (especially the 7 series) as bad as they seem?

I really appreciate anyones feedback on these issues! I'm sure I'll be checking the AMD64 forum a lot more once I get my machine rebuilt. Thanks!

~Vlad

WhiteDwarf · n00b Joined: 26 Oct 2003 Posts: 32 Location: Edmonton

I recently put together a new system (X2-4400, GeForce 7800GTX, etc).

I can't really compare 32 vs 64 bit code performance much. The only comparisons I have done is with one 3d game mod. I found that when CFLAGS are optimized for a X2, the 32 bit code runs almost as fast as the 64 bit code. However, I noticed about a 7% increase in the 64 bit code when running unoptimized, debug code (CFLAGS = -g3).

Installation was a breeze. It was no more difficult than any 32 bit install of Gentoo I have done.

The only stability problems that I have had were due to some too tight default RAM timings in the BIOS. A quick tweak to the settings and the stability issues went away.

I don't know what the problems with the newer NVIDIA cards are about. My 7800GTX has worked flawlessly for me (well, besides the fact that the drivers don't yet support some of the new AA modes, but that is supposed tol change once the new drivers are out). I'm currently running 1920x1200x60Hz (Dell 2405FPW) at 4xAA/16xAF for the gaming that I do.

It has definately been a positive experience. The X2 is a beast when it comes to compiling. There is no comparison to my previous system (AMD 2500+).

That being said, there will always be some issues when running a 64 bit system: You'll have to use mplayer-bin if you want to be able to use the win32codecs and have to use firefox-bin if you want flash. As well, there are a number of packages which are not available on amd64 which are available on x86. However, often times unmasking the specific package (or even adding a amd64 keyword to the ebuild in some cases) is all that has to be done.

The only other issue I encountered was one which seems to be a common issue on X2 systems: the clock running much faster than actual time. Adding "clock=pmtmr notsc" to the kernel params solved that issue for me.

Hope that helps

Sarpy Sam · Posted: Wed Sep 28, 2005 11:19 am Post subject:

I put together a new x2 system a couple of weeks ago and was very concerned after looking at the forums how much trouble I would have installing Gentoo. No problems, the install went really well with very few problems. Smoother than I expected actually so the developers deserve a big kudo.

My system is as stable as my old system, once I got a handle on the clock issue, and is much faster, but since my last system was a low end processor from 5 years that wouldn't take much.

If you're able to search out the forums for the occasional problem you should have no problem installing Gentoo.

Vlad · Posted: Thu Sep 29, 2005 3:10 am Post subject:

Thanks for the feedback. I'm glad to hear such positive responses! I really appreciate you two taking the time to give me your opionions.

Vlad

paulisdead · Guru Joined: 10 Apr 2002 Posts: 510 Location: Seattle, WA

There's a whole thread on PCI-E mobos with everyone's experiences with them on gentoo if you search this board for it, if you need help on picking a mobo.

Like the other guys said, the Lost Ticks and clock skew were a problem but we've found workarounds for most situations. I too am running an X2 with 7800GTXs and have had no problems (and am damn happy we'll finally have SLI support in the next driver release). I've run NWN, Doom3, and UT2004 without problems. The new nvidia drivers are rumoured to have the same multithreaded performance gains that the next gen windows drivers will have, so an X2 will help there.

I do have a 32bit binary xine package if you search this board as well, if you're more into xine over mplayer :wink:

<shameless plug>

Asides from compiling, the big thing that made me feel totally justified in getting the X2, was that my XVID encode times dropped by half in DVD::RIP. So if you're big into multimedia, you'll see a huge performance boost. My A64 3200 in my fileserver takes around 5-6 hours to encode most movies to a 700MB file, whereas my desktop with a 4200 @ 2.6GHz takes around 2.5-3 hours to encode a movie with the same settings.
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piwacet · Guru Joined: 30 Dec 2004 Posts: 483

Yeah I just want to echo that. Just built an X2, changing from p3-450, and it went quite well. The liveCD booted without any special parameters, and it recognized the X2 and used both cores. I sometimes had to issue the 'dhcpcd' command to get the liveCD to setup my internet (nforce4 board on-board NIC), which worked flawlessly. At other times (not sure why), when I booted into the liveCD the network was already running.

Installing went without a hitch, grub worked fine, all the packages I've emerged work fine. I haven't done a 'chroot' thing yet for 32-bit packages because I haven't had to.

I found that just adding 'notsc' to my grub kernel boot parameter rendered the 'lost ticks' issue harmeless. It's still there sometimes, but like 90% less, but the time source is stable and to my knowlegdge there's no detectable side effects. I eventually used both 'clock=pmtmr' and 'notsc' kernel arguements, because some people found that made the lost ticks error go away completely, but I still get it just as much as with just the 'notsc' option.

So good luck, don't worry, and there's plenty of help in the forums.

robbyjo · Guru Joined: 06 Apr 2003 Posts: 462

All, if any of you use X2 processors and ABIT AN8 SLI motherboard and you can see both cores, please let me know...

So far I have only one core enabled and the other core disabled because kernel complained "BIOS bug"...

ikshaar · Posted: Thu Sep 29, 2005 2:12 pm Post subject:

Check your BIOS for update. On MSI NEO4 second core was not visible until I flashed the BIOS with latest version. And of course use SMP kernel.
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"May God stands between you and harm in all the empty places where you must walk" - Babylon 5

piwacet · Guru Joined: 30 Dec 2004 Posts: 483

I think there's someone else on the forum with an abit motherboard and an X2 who's also having trouble getting both cores recognized, I'd search for that thread.

Good luck, and let us know if we can help.

robbyjo · Guru Joined: 06 Apr 2003 Posts: 462

piwacet · Guru Joined: 30 Dec 2004 Posts: 483

Ooh - sorry, dude. :roll:

Good luck.

olivierweb · Posted: Sun Oct 02, 2005 10:35 am Post subject:

I'm curious about the gain of the X2 over 'normal' AMD64.

I think I'll have to mount a computer for shared sevices (database, SVN repository) and I can bear installing Mandriva (maintaining is headache, installing soft is... ) .

If compiling is again shorter, it will be easier.

Can you post the time for compile xorg-x11 ?

this is mine

AMD64 3000+ slot 754
Asus K8N
512Mo

paulisdead · Guru Joined: 10 Apr 2002 Posts: 510 Location: Seattle, WA

xorg is a terrible example of compile time on a dual core/smp system. iirc they disable multithreaded compiling on that package because it breaks stuff, I know I only see 1 core being used during the compile of it. A better example would be glibc or firefox or something.

olivierweb · Posted: Sun Oct 02, 2005 4:37 pm Post subject:

ok, this is very impressive.

justincataldo · Guru Joined: 15 Jun 2005 Posts: 376 Location: Australia

At the moment I've got an Athlon64 3500+. It beats the crap out of my dual Xeon 1.7GHz system (which are not hyperthreaded).

My motherboard supports X2 processors, so I'd like to get one one day, as I do a lot of media work. I'm sure I could take advantage of the extra speed. :smile:

Although, I've got a problem with my motherboard at the moment. It doesn't boot sometimes when I restart the machine, and I end up having to press the reset button a few times to get it to start. I've got the latest bios installed, but that didn't fix it. So I might end up having to buy a new one...
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Core i7 2.67GHz with 12GB DDR3 RAM.

fserafin · Posted: Thu Nov 24, 2005 6:21 am Post subject:

justincataldo check your switches out on your case and check you power supply first before you toss your motherboard and as always check for warrenty

here's my times on amd64 x2 3800+ with 1gig of dual channel kingston memory on a gigabyte bord k8nf-9
but i don't think that these times mean much because people could have other apps etc running when emerging them
and have different use flags

but i do say this i find that my system is nice and fast

j-m · Retired Dev Joined: 31 Oct 2004 Posts: 975

glibc is a bad benchmark - the ebuild forces MAKEOPTS="-j1"

Juha · n00b Joined: 09 Feb 2004 Posts: 36 Location: Finland

I didn't read the whole thread but by answering to the original question.

I build my setup with 3800X2, 2GB ram, ASUS A8n-E, 6600gt pc-e, nexus 500W, and one sata disk for production server
and that's why I have been using all 32bit system. I didn't have any difficulties to get whole
system working but as I already mentioned, it's all 32bit.
The system is been running since beginning of October and is rock solid. I use gentoo-sources.
Compiling is extremely fast and in my case, distcc rocks hard.

This is my first AMD system and I've been very happy with it. =)
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-Juha-

paulisdead · Guru Joined: 10 Apr 2002 Posts: 510 Location: Seattle, WA

halfgaar · l33t Joined: 22 Feb 2004 Posts: 781 Location: Netherlands

I'm planning to build an AMD X2 system as well, but I have a question. Most people seem to reinstall their system. Is it possible, to just plug in my HD with my current Gentoo in the new system? It's compiled with "-O3 -march=i686 -mcpu=athlon-xp -pipe". So, it's i686 code, optimised for and XP.

The switch to 64 bit I'll consider later, it's just that I hate reïnstalling, because I have put quite some effort into a proper system.

ikshaar · Posted: Sun Nov 27, 2005 3:26 pm Post subject:

Sure you can. You can keep your system 32bits.

As you have change some hardware, you might need to boot from a liveCD to chroot and rebuild kernel if driver needs have changed, but other than that it should work.
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"May God stands between you and harm in all the empty places where you must walk" - Babylon 5

halfgaar · l33t Joined: 22 Feb 2004 Posts: 781 Location: Netherlands

I think recompiling the kernel from the working system shouldn't be a problem, so no live cd needed for that.

The reason I asked, is because of my CPU optimizations. I know it can run 32 bit, but can it also run i686-specific/athlonxp-optimized code. I686 shouldn't be a problem, but perhaps the optimizations for athlon-xp will make it very slow...

JohnY · Apprentice Joined: 26 Jul 2002 Posts: 265

I have an X2 4400 with a K8 optimized kernel and a 32 bit system with an i686 host and athlon-xp flags. I installed it fresh on an Asrock 939DualSataII with an sata drive on the sataI controller. Works fine and it's quite a speed increase over my 2.0 GHz AthlonXP TbredB. Very responsive and just as solid.

JohnY

wesw02 · Posted: Sat Dec 03, 2005 5:59 am Post subject:

i agree with everyone else, I just built my first 64-bit system and I am still amazed at how smooth it was, i figured with my x2 and geforce 7800gt i would have had some problems, the only snag I have run into so far is that I had to used the masked nvidia drivers to get my card to work.

This community has been a great help, if you run into any problems, I'm sure someone will know the answer

nxsty · Veteran Joined: 23 Jun 2004 Posts: 1556 Location: .se