Upgrade: PIII to AthlonXP, CFLAGS and such

neonik · Guru Joined: 08 Oct 2003 Posts: 501

I'm planning to upgrade my system and use an Athlon XP CPU instead of my present Pentium 3. I have, however, a Pentium 3 optimized system, in my make.conf I've got PIII/4 optimization compiler flags. Now to the question self: Will there be any noticeable performance leaks with the new CPU and would you advise me then to recompile the entire system using the appropriate Athlon XP CFLAGS?
As far as I know, the both CPUs have almost the same architecture. AMD's Athlon CPUs are anyway in the group of i686 processors, so are the Intel's >= Pentium III CPUs. My kernel is optimized for Pentium III, as well. I know I'll have to recompile it but will I be able to start the system as usual at all?

Well, the questions might be stupid and the answer clear, but I'm quite a newbie concerning this issue (never used processors other than Intel) and I don't know much about software-processor relationns. Therefore I'd love to hear your advises/suggestions and ideas.

neonik · Guru Joined: 08 Oct 2003 Posts: 501

I also would like to ask whether I should take the mainboard with a nForce2 chipset or the VIA Apollo 600.
I heard there were some problems with nForce2 mainboards. And also, what's the advantage of the nVidia's mainboards?

ewan.paton · Posted: Sat Dec 27, 2003 11:06 am Post subject:

the athlon xp has all the same optimizations as the p3 like mmx and sse1 extenions so it should be a case of pluging the drive in and it will run it also has 3dnow extensions which are probably just mulimedia stuff like mmx & sse as long as you havent optimised for a p4 which have sse2 extensions you should be ok. personaly i would remake the kernel though for paranoia sake.
_________________
Giay tay nam | Giay nam cao cap | Giay luoi

neonik · Guru Joined: 08 Oct 2003 Posts: 501

Thanks for your reply, ivan.paton. It confirms my suspicions

Well now one more thing that also has confirmed that upgrading should go fine: I've compared the flags available for the both CPUs.
My Pentium 3 has following flags:

ewan.paton · Posted: Sat Dec 27, 2003 5:36 pm Post subject:

from what a remeber the nvidia is meant to be faster and was slightly more hassle about 6 months ago, most amd xp boards should work fine out the box now but you may wish to google for a more reliable source than my memory.

just for kicks you might want to run some benchmarks before and after recompiling, also unless you have a very fast hard drive i would try 02 it produces smaller binaries which compile and load faster
_________________
Giay tay nam | Giay nam cao cap | Giay luoi

neonik · Guru Joined: 08 Oct 2003 Posts: 501

Thanks for your reply, ewan.paton, again.

Now I guess I have finally realized why I had set CFLAGS with the -O3 optimization instruction when I was installing Gentoo: My HDD is pretty fast.

Thanks again. I think when it comes to a system upgrade you never know what to choose, unless you're certain

Now to decide whether ATi Radeon or nVidia GeForce...
This is all because it's all almost the same...

Thanks again for the replies.

ewan.paton · Posted: Sat Dec 27, 2003 9:29 pm Post subject:

my vote has to be nvidia all the way under linux its opengl so all the directx 9 probs dont matter but if you are after a £300 monster for god stake wait i hear march is when they start rolling out the new lines which are twice the speed. i have 2 diffrent nvidia and 2 difrent ati cards the nvidias take 5 mins to setup and have good drivers, after 7 months of using gentoo i still havent got dri working i also think nvidia are more commited to linux.
_________________
Giay tay nam | Giay nam cao cap | Giay luoi

neonik · Guru Joined: 08 Oct 2003 Posts: 501

Yeah, that was also my thought - that nVidia cards are better supported on Linux systems than the of ATi. I was, however, going to purchase some kind of Radeon 9800XT or GeForce FX 5950. Had stopped once at the Radeon card due to its support for OpenGL 2 whereas the nVidia's card only supports OpenGL 1.5. Don't really think it's much of a difference, or even if it was so, it would't be worth the price of the extra 60 EUR/USD to the price it's going at and the work required to be done to succesfully set up the card and so on.
I've also read an interesting article recently that nVidia may release a new Detonator providing some new features. But I doubt it would enable features the graphics card is already enabled for. Or would it?

So I guess I'll wait then till March...

Thanks again.

Su-34 · Posted: Thu Feb 26, 2004 6:00 pm Post subject:

My Pentium 3 has following flags:

neonik · Guru Joined: 08 Oct 2003 Posts: 501

You don't need them all, mcpu=pentium3 would involve inclusion of all proper compilation flags. Compilations like -march=pentiumpentium3 -march=pentium3 -msse and so on are not required if you have just -march=pentium3. Just read manual pages for GCC (man gcc).

Default offered by Gentoo: -O3 -march=pentium3 -fprefetch-loop-arrays -funroll-loops -pipe. You might want to replace -O3 with -O2 or if you have not much HDD space with -Os. -On (n=s|0|1|2|3) flags specify how big the binary will be and how much it will optimize.
_________________
Best regards,
neonik

netshot-0.0.8 - script that takes screenshots, generates their thumbnails and uploads them all! (has not been updated).

Su-34 · Posted: Fri Feb 27, 2004 10:06 am Post subject:

or if you have not much HDD space with -Os.

sorry does not -Os optimize only cpu with very small cache? (like k-6, pentium pentiumpro, ecc..)????

thank in advance

neonik · Guru Joined: 08 Oct 2003 Posts: 501

Su-34 · Posted: Fri Feb 27, 2004 5:30 pm Post subject:

thank neonik

is this link http://gcc.gnu.org/onlinedocs/gcc-3.3.3/gcc/i386-and-x86-64-Options.html#i386%20and%20x86-64%20Options

a good reference to find information on optimization flag usage?

or 'u know a better one?

thank 'u a lot

neonik · Guru Joined: 08 Oct 2003 Posts: 501

That link will give you some information, but, as always, the best source is code, thus read "man gcc". I've seen many people include in their CFLAGS many many funky freaky additional flags that are already included by -march=pentium3 or -mcpu=pentium3 and other flags, it's not necessary therefore.

Read also this: http://www.freehackers.org/gentoo/gccflags/flag_gcc3.html
_________________
Best regards,
neonik

netshot-0.0.8 - script that takes screenshots, generates their thumbnails and uploads them all! (has not been updated).

altorus · Posted: Sat Feb 28, 2004 2:38 am Post subject:

I would highly recommend a nforce2 based motherbord. They are fast and stable. Just one thing if you are running an early 2.6 kernel, disable APIC - tho i beleive this has been fixed in 2.6.3 and onwards

Given the video card discussions i figure its safe to asume that you aren't going an built in gfx nforce2 board - very good idea, this is the only thing that i have found to be unstable.

Ooh and the linux section over at the nforcershq.com forums are your friend