Topic: Motherboard and maximum CPU speed

[Sandra]

I am in the process of trying to find the cheapest/best option of upgrading a friends PC.

One thing that has always puzzled me is why does a specific motherboard only take a certain range of CPU speeds.
What is the limitting factor,assuming that they all have a 133 FSB and the same type of CPU ie slot 1 ,socket 478,socket A etc.
Is it the BIOS or the chipset or something else ?
If its the BIOS can the BIOS be upgraded at a later date so that a mobo that will only take a maximum AMD XP 2100+ today will be able to take an AMD XP 2400+ in a few months time ?
If it is something else,can that be upgraded or modified somehow to enable a faster CPU later ?

Answers (preferably not on a postcard   ) before 9am tomorrow please,as that may be the time we need to decide what we are buying  

[Robotochan]

A lot of the time the maximum is out of date, take my other PC's mobo for example, it has a 2000XP although the box and manual say 1600 max. I think it has something to do with the hardware. For a cheap CPU I'd suggest www.ebuyer.co.uk as they have a sale or something on £80 for a 2600XP

[Sandra]

Thanks Robo we have been looking on there as they seem to be very competative.
My preference is to get a mobo with a capability of 3ghz or more,even if that puts the price left over for a cpu of a lower speed of only possibly between 1.5 and 2 ghz.
As what costs £X now will be £0.5X in a few months  

[Simon]

Answers (preferably not on a postcard   ) before 9am tomorrow please,as that may be the time we need to decide what we are buying  

You'll make yourself ill getting up at that time in the morning, Sandra!  

[Sandra]

I know its scary isnt it  

In fact I will have to be up at 8am as hes coming at 9am ish  

Hardly seems worth going to bed so I may do an all nighter that way I wont oversleep  

[Sandra]

Just in case only Robo and Simon saw this thread I will "re open it" as,although the deadline has now passed,I would like to know the answer please  

[Simon]

What was the question again?    Oh, just read it - no good asking me Sandra!  

[Robotochan]

There is not much point in look for a mobo that can take more than your putting into it now as Athlon64 is coming out this month hopefully   I found a 2400XP, cooler and mobo bundle on E-bay for £90 a few weeks back  

[ketamininja]

Generally the BIOS is the main factor in the CPU speed.

The BIOS will request information from the CPU to make sure it knows how to interact with its architecture. The cip responds with a certain language, which the BIOS translates.

The newer CPU's may have a slightly different architecture, and therefore may speak a different language. Sometimes the BIOS will say that you have a 2000+ XP CPU, and another BIOS will say you have a Athlon 1650 Mhz or whatever, simply because the command to say what the chip is cannot be read by that BIOS... follow me so far?

A BIOS update if available will usually support the highest available chip at your mainboards FSB speed.

[bat69]

There are limiting factors as quirks of the mobo architecture and the amount of FSB multipliers available.

As you know, chips use the FSB (MHz) with a multiplier to achieve the xGHz speed. Also the memory, PCI slots etc use the FSB speed with multipliers and dividers to achieve their running speed.

In order to get something that can be used later with a more powerful chip, ensure it can be capable of using the latest technology (ignoring 64bit processors for the minute) so something that will take an AMD XP3000+ will work with a 2400+ now but can have a 3000+ dropped in later (when they are as cheap as candy)

A mobo that can take a faster processor will almost certainly be able to take the faster memory. And to be quite honest I think going for more and faster memory with a lesser processor will be better than trying to get the fastest processor you can for your money. You can always overclock it  

Hope this helps Sandra

[Sandra]

In order to get something that can be used later with a more powerful chip, ensure it can be capable of using the latest technology (ignoring 64bit processors for the minute) so something that will take an AMD XP3000+ will work with a 2400+ now but can have a 3000+ dropped in later (when they are as cheap as candy)

A mobo that can take a faster processor will almost certainly be able to take the faster memory. And to be quite honest I think going for more and faster memory with a lesser processor will be better than trying to get the fastest processor you can for your money. You can always overclock it  

That was my idea Bat thanks, unfortunately that particular project has been shelved for the time being  

I would never overclock as most CPUs over 2ghz are plenty fast enough for most of todays needs and why push something to the limit unnecessarily  

[Robotochan]

My next PC will be an AMD64