duel cpu mainboards

obi-1

i am going building a new spec during the summer and i am thinking about building a duel processer system and

i remember someone saying to me that when you are ordering the chips for the system that you have to say that they are for a duel system - or else they will not work.


is this true ?

Gerry

Could you be a little more specific? If its an intel system, you will need to buy p4 xeon chips, which are a different form factor to ordinary socket 478 p4 chips, (xeon has 603 pins). If its amd you will need to buy athlon mp chips instead of xp, but there isn't too much of a price premium any more.

Spunog UIE

what would the processing speeds be like with a dual do ya know? Say ya had two 2ghz chips, would it be a 4ghz comp then or like 3 or somethin?!

Gid.

Kali

Gideon.. theres not a linear improvement in performance (i.e. your PC will not be twice as fast with 2 processors).
your operating system or software must also support dual/multi processor configuration natively... otherwise the extra cpus will basically just be going unused.

Take quake3 as an example.. turn on the smp option and iirc theres only in the region of a 15-20% increase in fps...

It's like my understanding that at a basic level the re-emergence these days of chips with very deep pipelines makes it even harder to extract performance from a multi-processor setup, e.g. the scheduling of events between the two chips is the one bottleneck and it helps enormously if the software can do this.

bear in mind that athlon mp chips still cost a bit more than say an equivalently clocked athlon xp (to the region of €120, and dual socket a boards arent the cheapest iirc), so you're talking €280 more.. which imo is usually better spent elsewhere, considering the performance difference on say a graphics card or spend it on the single cpu itself.. (i've no idea of the p4 xeon costs, but I'd imagine they're not a pretty sight).

Spunog UIE

ya knew that somehow, otherwise everyone would be at it.
Thx.

obi-1

I am unsure yet about AMD or Intel. Is there much of a performance increase between the two manufactures in the MP or Xeon range.

Also any ideas on motherboards need something for the dual processors (amd or intel) it has to have a fast bus speed scsi and ide interfaces possibly with raid. Two AGP ports would be nice. Basically a high spec mobo.

I have my mind set on building a powerful spec this summer its keeping my mind off the leaving cert also.

Obi1

Kali

a motherboard two agp ports? none exist afaik
and if there was it'd be a pretty messy situation, two apertures in memory at the same time and you'd need some sort of addressing system for the ports, which (well in my mind) would sort of go against the whole point of AGP.. (i.e. direct access between the graphics system and the main memory)

paws

Regarding dual systems performance: your apps need to be multithreaded to take advantage of both chips at the same time. Most 3D apps, decent video progs and Photoshop for example are multithreaded. Performance increases range from small/mediocre (e.g. Photoshop) to huge (3dsmax dual rendering can reach 190% the speed of a single CPU system).

Even if an app isn't multithreaded, you've still got a whole CPU left over for other programs to use. My current system (dual celery 366s@550Mhz) has been a dream to use, and hardly feels its age. Also if one app locks up a CPU, you can still work with the other one. In general dual systems feel far more responsive than single chip systems.

Cons: duals can be a bitch to get going properly, and apparently AMD duals are even harder That said, I'm about to build a new dual AMD system. I can't guarantee it'll work sweetly first time, but I've researched every bit to death so hopefully it'll all work together.

Con 2: more heat produced, so harder to cool.

Here's what I'm planning to order. I'll report back when (if!) its assembled.

Chieftec mid-tower DX-01B-D
Antec 430W TruePower PSU (v.quiet)
Tyan Tiger MP mainboard
2 x AMD MP1800+
2 x Thermalright AX-7 CPU heatsinks
4/5 x PAPST 8412 NGML 80mm 4-pin fans (v.quiet: 2 for CPUs, 2/3 for case)
2 x 512Mb Crucial ECC DDR Ram
Gainward Ti4600 w/Firewire
1 or 2 Western Digital 800JB 80Gb HDDs (not quietest, but v.fast)
Samsung 16x/48x DVD (supposedly quiet)

Keeping it quiet is important for me, since my current machine isn't


paws

obi-1

paws that spec you are building is something like what i have got in mind, a beast

Kali sorry, for some strange reason i thought that they existed

Gerry

Argh I'm too tired to post loads, but this is an interesting thread
Basically I think a dual system is worth the money if you use your computer for serious, heavy work like 3d rendering, video/audio processing/encoding/decoding, on a regular basis. As paws says, you can run 2 singlethreaded apps at the same time, so you can take advantage of the 2 cpu's if you are a power user.
The thing to remember is that a dual system technically needs twice the memory bandwidth, of course this is impossible but you should look at optimizing memory bandwidth as much as possible ( eg running on a high fsb like 166, tweaking the hell out of the bios).
Finally I do think that dual systems just feel a hell of a lot faster doing any sort of work at all. I use a dual xeon 2.2ghz in work, and it absolutely flies along for development work, but I am building a p4 1.6@2.5 ghz at home. In windows it feels sluggish by comparison, but is waaaay faster in games, because of the higher clock speed and higher fsb (155 vs 100 ).

paws: That looks like a well thought out spec, but you may want to consider the msi k7d master board for overclocking. I think the western digital drives are very noisy, I'm using ibm 120gxp drives in the current machine I'm building. While technically not as fast as the western digital, it seems faster than the ibm 75gxp, 60gxp, maxtor 740dx etc, and almost as quiet as the seagate barracuda IV ( ie its much quieter than previous ibms). I've measured real world performance of 35 megs a second with this drive, and thats plenty.

paws

Gerry: interesting tips. I wasn't planning to overclock the system at all, since I'd rather stability than outright speed. As for the WD drives, I was also concerned about the noise until I had a gander at storagereview.com. According to them, the WD800JB is actually quieter than a 120GXP...

http://www.storagereview.com/articles/200205/20020529WD800JB_6.html

I have a deskstar at the moment and I like it a lot, and it seems the 120GXPs don't have the horrid problems the 75GXPs had. However if you go by storagereview the decision is fairly clear-cut...

More important than ANY of this though is that I'm seriously worried about a dual AMD system now. I've been reading a LOT of people's problems with dual AMDs in general, and the combo of a Tiger MP and the Gainward seems to be just asking for trouble. I haven't found one person yet anywhere you claims to have a Tiger MP+GainwardGF4 working together fine.

I really _really_ want a dual system, but everyone I know in the real world who has experienced AMDs has had trouble with them. My current machine here in work is a POS assembled by Scan, Athlon 1600+. It's still got stuttering problems that we can't sort out, after replacing the CPU twice. Each replacement made the system better than before, which is scary.

I'd get dual Xeons in a flash if I didn't have to mortgage my house to get them. The sad truth is that I'm now considering either
a) a fast single CPU system (preferably P4)
b) dual PIIIs

More to follow...

:-/

paws

PS. Colleague of mine was going to switch from a Mac to dual Athlons, put together by CD Soft (in Kildare). Two weeks after ordering it, and multiple calls later, he's cancelled the order. Not because he's impatient, but because CD Soft have had massive problems getting the system running. Perhaps because they were trying to integrate the Gainward GF4. If they can't build a stable system, I don't fancy my chances without incurring multiple aneurysms...

Gerry

Erm, I'm sorry but I'm having heart attacks here imagining cdsoft trying to put together a dual athlon system. Hopefully without being done for slander, they are fairly typical small irish pc builders, who are grand when they get a load of intel parts and it works first time, but they will not have done any research on the amd side of things (or very little).

How about just getting a different graphics card?

Looks like I messed up big time on the hard drive, the wd 120 gig is noisier than the ibm 80, but the wd 80 is quieter as you say.

paws

Re CD Soft: I have no personal experience of them, but my company has used them for years to provide trouble-free PCs for exhibition installations. However I guess dual Athlon systems would be a bit unusual for them.

I'd really like to get the Gainward because it kicks ass, comes with a Firewire card, and is supposed to have a quiet fan. Not much good though if it BSODs the system, and I can always get a separate Firewire card. I don't know whether its the Gainward in particular, all GF4s, or nVidia's drivers that are the real problem.

I'll check out that MSI board you mentioned, thanks.


paws

Gavin

Just a quick comment. I have a dual p3 450 ( slot1 ) and am upgrading to dual 933's in a few weeks. I do a lot of Java stuff and it helps with that, but apart from that.. I've not noticed a major difference... Then again it's a good while since I've used a single cpu lowend machine.

Linux seemingly has better support for smp than win2000, but I'd take that with a pinch of salt.


Gav

paws

well I ordered the spec above, but I got an Asus A7m266D mboard and 2 80Gb Western Digital HDDs instead. Half from Komplett, other bits from overclockers.co.uk.

Ordered from Komplett before the match, they had shipped it by the time it was over


I'll report back if it works.


paw