# Choosing a Motherboard. 400, 533, or 800Mhz FSB?

## Lul2x

Hello. I was just wondering how much of a difference there is between motherboards that have 400, 533, or 800MHz FSB. Is there a noticable difference between them when using your comp? Has anyone had experiences with different frequencies? Basically I'm just looking for input from anyone on the differences that each of these has and the effects they will have on your overall computer performance. Thank you.

----------

## taskara

yeah.. the higher the number the faster  :Wink: 

I think 800fsb is the way to go.

but if it's too expensive, then get a slower cpu, but run it at a faster fsb.

always get a high quality mainboard, as fast as u can afford - then u don't cut yourself off in the future..

for example, get yourself a mainboard that has good linux support, that has 800 or higher fsb support.

u could get yourself a 2.4ghz pentium 4 that runs at 18*133fsb

18*133 = 2400

then u can up the FSB to 166 giving you a 3ghz machine for the price of a 2.4

18*166 = 3000

100fsb = 400

133fsb = 533

166fsb = 667

200fsb = 800

or u can get a 2600 that runs at 200fsb (13*200 = 2600)

u can prob get it to run at 3.2ghz if u have the right cooling and mainboard -

13*250 = 3200

or at

13*230 = 3000

250fsb = 1000

anyway the point is, the higher the fsb the faster the cpu, and believe me, the pentium 4 can use the help.

I would not want to go slower than 800fsb, but if u do, keep in mind that you have to have GOOD QUALITY pc3200 or higher RAM  :Very Happy: 

----------

## Lul2x

Wow. All those numbers are pretty confusing but i get the jist of it. Is there somewhere where I could learn what all those numbers mean and how they work with each other? I really would like to know what I'm getting before I buy. Thanks for the help!  :Very Happy: 

----------

## taskara

no problems

basically a cpu has two clocks.

an internal clock and an external clock.

let's say we have a 2000Mhz cpu. how do we get 2000mhz?

well we have an internal clock (which is called the front side bus - or fsb for short)

the fsb may be running at 200 mhz

now in order to get 2000 mhz, we have to multiply 200 by 10.

the multiplication of the fsb is the external clock.

200*10 = 2000mhz

internal clock * external clock = cpu mhz rating.

generally, the higher the mhz the faster the cpu (well when comparing the same type of cpu, like pentium 4's with pentium 4's)

maybe the cpu runs at 133 fsb

that would give 133*15=2000mhz

so we have two pentium 4 cpus, both running at 2000mhz.

one runs at a fsb of 200 and the other runs at a fsb of 133

which will be faster?

the cpu running with the faster fsb of course  :Smile: 

to complicate the situation further, the pentium 4 QUAD PUMPS the fsb.

u don't need to understand this, just know that when a pentium 4 refers to its fsb, it's multiplied by 4 (cause it's quad pumped)

so a pentium 4 with a fsb of 800, is actually 800/4 = 200fsb

----------

## Jimboberella

What do you want to do with your PC?

If you do alot of 3d gaming or modeling, large image manipulation etc then 800mhz will be better. If you just browse the web and do email, word processing etc then 400mhz will be fine.

But 800mhz will also show a benefit at compile time (Gentoo = lots of compiling), assuming you have enough physical ram (optimally >=512meg)

If you can afford the faster one get it, because you wont be buying "outdated" hardware.

----------

## Antimatter

but before you jump into overclocking i would like to stress the importance of GOOD cooling.  i myself am building my own custom watercooling system the only parts that i have bought is the two waterblock one for the CPU and one for the radeon 9700 pro and a very nice pump, everything else is being bult by me, heh i have an lian-li 75 case and those thing are massive so i simplely knocked out the top four 5.25 inch bays to stick in a few fans then i'm running a duct though the entire top part to the back which has another set of fan, so heh i got a little windtunnel running though the computer heh.

anyway enough ranting about cooling. anyway now onto memory, when youre overclocking depending on how far you want to push it you might want some of the more high quality and more expensive pc3500 and up. i myself am using 2x 512 meg stick of pc3500 corsair XMS memory.

anyway i'm not sure what other motherboard has the feature but i think a few have the divisors, basically you can run the bus speed at different speed for the CPU/memory anyway i think you have 1:1, 3:2, 5:4 and probably a few other divisors but basically what that means is you can overclock your CPU even higher.

anyway memory like pc3500 has a bus speed of i belive 233 anyway i'm very very rusty on overclocking so if you want serious information about overclocking i would recommend you head over to [H]ardForum its a hardware website and is where i learn most of my hardware stuff from theyre pretty friendly imho.

anyway back to the memory thing i'm a little rusty but let's see if i can't atleast rember the basic of it.

Intel has quadspeed bus so basically you take the bus speed and multiple it by 4x so thus the "base" bus speed is 200 mhz but its a quad bus so that is multipled to 800mhz anyway with regards of memory. let's say we got a stick of pc3500 ram which is i think 233mhz bus speed or so. now that means we can bump the base bus speed to 233mhz which is 932 mhz quadpumped, which would bump our little 2.4c to about 2.7 ghz now those little chip can hit 3.2 easely with good cooling or higher, ive seen some of the more extreme people who use like liquid nitrogen hit 4.0 ghz stable. but that's beside the point, anyway memory can be pushed a bit over their rated bus speed such as say our 233mhz memory can be pushed up to maybe 250mhz but after a certain point it starts to crap out, that's where the divisor comes into play as i recall we got 1:1, 3:2, 5:4 its basically divisor of the CPU "base" bus speed so we can bump our cpu even higher, so first we push the memory's bus speed untill it start to crap out, let's say we manage to push our pc3500 ram to about 250mhz bus speed, now its starting to crap out around that point, but we still want to go higher so we can use the divisor, so let's use a 3:2 divisor with that divisor we can run our "base" cpu bus speed up to about 375mhz and the memory bus speed will then be running at 250 mhz, anyway 375mhz base bus speed would yield an cpu speed on our little 2.4c, it would hit about 4.3ghz theoricaly with ungodly good cooling, anyway most people hit about 3.0 to 3.4ghz with the 2.4c and some luck.

now regarding the quad bus speed, due to how intel build their chip, they have 4 bus going out at 200mhz each which combites to an total of 800mhz, anyway if youre wondering about the dual memory thing, basically pc3500 memory are running at 466mhz because i belive each stick has 2 bus on em which takes the base speed of 233 and doubles it to 466 but still 466 isn't fast enough for the 800mhz quad bus thing that intel has going for them, so that's where the dual memory thing comes in, basically you stick two same speed and size ram aka pc3500 512meg stick i sticked two of em into my computer, and the way that the bus is setup, 2 bus from the cpu goes to one stick, and the other goes to the other stick so it would yield an total of about 932mhz bus speed total for the memory or so.

 disclaimer: some information contained within the above post might be inaccurate but its as accurate as i can rember, and i think i got it right but if you see something wrong in it be sure to nickpick it okay  :Smile:  and sorry if the above post was a little confusing, i'm sort of a hardware/software guru 

anyway for my system spec.

its 2.8c overclocked to 3.2+ ghz with watercooling

2x512meg stick of corsair XMS pc3500 ram

2x37gig 10k raptor SATA harddrive

2x200 gig western dightal IDE harddrive

radeon 9700 pro with watercooling on it <- overclocked to

dvd player

cdrom burner

abit IC7-G with a onboard gigabit ethernet card which i hope to god will work for linux

----------

## Lul2x

hmm, it looks like 800 is the way to go. I guess it's just another weeks savings   :Rolling Eyes:  . Boy, these things get expensive!

----------

## Kihaji

Also keep in mind that both Intel and AMD are going to a new socket with their next chips so the 800's will allow you to get the fastest chip out now, before the socket changes. Thereby prolonging the use of your machine before you need to upgrade again.

----------

## Lul2x

so for the next cpu i'm going to need a new motherboard in order to get the right socket? That's not too good, but then again, motherboards are not EXTREMELY expensive.

----------

## Malakin

In case you're interested in a simple answer to your question :) may I suggest an Asus P4P-800 motherboard, note there's several models but the deluxe model isn't much more and it's quite nice although any of them are good.  For the CPU a Pentium 4C 2.4Ghz is probably the best bang for buck right now. Going to a 2.6Ghz increases cost by 27% and performance by about 7%, cost/performance gets even worse the faster you go. A P4P-800-deluxe and a P4C 2.4Ghz combined should run you about $300usd.

http://www.asus.com/products/mb/socket478/p4p800-d/overview.htm

For P4's I agree that 800mhz fsb is the way to go, it barely costs any more these days unless you're trying to assemble a low end system.

If you want something cheaper you can get an Athlon XP 2500+ with an Asus A7N8x-Deluxe (nforce2) for about $200usd.

http://www.asus.com/products/mb/socketa/a7n8x-d/overview.htm

Cheaper still an XP 2500+ with an Asus A7V8x-X (KT400) for about $150usd, half as much as the P4 system and it's performance will be pretty close although the motherboard has fewer features.

http://www.asus.com/products/mb/socketa/a7v8x-x/overview.htm

----------

## Lul2x

Thank you for the post Malakin. It just so happens that I was looking at that exact board.   :Very Happy:   This reinforces my decision and that is most likely the one i will get. As far as the cost/performance issue, that is quite a disappointment. I was looking into a 2.8GHz P4 but I will definately reconsider getting a 2.4. One more thing... what does the 'C' mean in  Pentium 4C 2.4Ghz? Thank you everyone for the help and comments!!

----------

## taskara

the C is the latest chip revision isn't it.. before the prescotts come out..

so a "C" is what you want...

it's like College reversed in the IT world  :Wink: 

"Man I hope I get a C this time!"

----------

## taskara

BTW if u DO go that board, it does have SERIAL ATA / RAID that you can use if u want to go serial hard drives

 *Quote:*   

> ICH5R with Integrated SATA and RAID 0

 

it also has VIA raid, but I don't htink that is well supported.

the intel raid is ONLY supported in 2.5 / 2.6 kernels as far as I am aware (under SCSI low level drivers).

----------

## taskara

[url=http://www.asus.com/products/mb/socket478/p4c800-e_d/overview.htm]this[/url is the big brother (intel's latest chipset, i875 - as opposed to i865)

the 875 USED to be much faster, but now they have unlocked some technology int he 865, which makes it just as fast as the 875

however that board has a promise serial ata raid controller, incase you want to run 2.4 kernels..

----------

## Antimatter

how about take a look at the IC7 board, its quite nice imho i'm using one in my newest computer, and it comes with a onboard gigabit LAN and i hope it will work with linux if not i can just put down 50$ for a cheap NIC

----------

## taskara

I have played with the Abit IC7 - they are a nice board too..

----------

## Lul2x

I will continue to look into the boards. As for the P4C thing. I cannot find a P4 CPU that says P4C. Is it not usually included in the name of the CPU, is it something I have to look harder for? I just can't seem to come across it. Thanks

----------

## taskara

some suppliers list it, others don't.

it's the model number which should be on the serial of the cpu. u need to look at the box.

or ask the supplier for a C model

and check before you open it  :Very Happy: 

----------

## Malakin

 *Quote:*   

> the 875 USED to be much faster, but now they have unlocked some technology int he 865, which makes it just as fast as the 875

 Intel fixed this so 865 boards are unable to use PAT now. I'm not sure about the current shipping boards, if they're using the newer rev 865 then they won't use PAT but they still might be going through the older chips. I'm sure one of the enthusiast sites has more info on it. The performance difference between the 865(no pat) and 875 is very small though and it's not worth the extra money if you're going for the 875 just for the extra performance.

 *Quote:*   

> what does the 'C' mean in Pentium 4C 2.4Ghz?

 The "C" means the 800mhz part that has hyperthreading. The non C would be 533mhz and would not include hyperthreading (except for the 3.06ghz model).

If it's an 800mhz part then it's automatically a "P4C" (well this is true as of writing this anyways)

----------

