im using AMD2400+(thoroughbred) with pc2100 512mb ram. Im using a GA-7vrxp mobo which allows me to increase bus speeds from 133-165 in 1mhz increments, i can also change agp, ram and vcore voltages. I am using on overclocked geforce 3 ti200 vid card also.

when trying to overclock i can only get my bus speeds to about 140 (133 being the standard) and i am unsure what is bottle necking my OC'ing. I guess its the ram and my mobo can take ram of faster speeds. I want to get large gains out of my CPU as i have good air cooling.

Currently i am running adm2400 @ 2.1ghz.

q1. Is faster ram such as pc2700 and/or pc3200 backward compatible? i.e. can i use it at 266 speed instead of 333 or 400???

q2. If it is when overclocking a cpu with fsb 266 do i run the ram at 266 also then overclock my system? or do i run the ram at 333 and my cpu at 266 and then overclock?

all help will be much appreciated people - thank youy very much in advance.

1. yes, they are backward compatible

2. you'll get better performance if you run "in sync"...that is, both memory & CPU at the same bus speed

OK, here's a couple of suggestions...

- your CPU is unlocked...multipliers can be manually adjusted thru a DIP switch on the board, near the CPU. Try a lower multiplier with a higher FSB. You'll gain more performance with a higher FSB, than with just a higher CPU speed. In other words, your CPU's default speed is 2000mhz (15 x 133)...you should see better performance at 12 x 166, even though it's still clocked at 2000mhz, than you would at say, 2133mhz (16 x 133). You mentioned that your FSB settings run from between 133-165mhz. Your board has a KT333 chipset which is designed to run at 166mhz - you should be able to take it as high as 200mhz FSB...but you'll need PC3200 RAM to pull it off. Right now, your RAM is holding you back.

- run your RAM at 2.7v

thanks 'jam'

ok a few things - im pretty sure i cannot use cpu's wiht 333 fsb, the only way i know how to is to go into my bios setup and change to 165 which is the maximum i can set it too - this feature in my mobo to chage fsb 133-165 is an overclocking feature implemented for overclockers.

im pretty sure the kt333 refers to the maximum speed ram i can use i.e pc2700(ddr 333).however, i am still thinking of buying ddr400 pc3200 and overclocking using this is this a good choice? or should i just use ddr333 pc2700?? - money for either is not the issue system performance and stability are :)

as u instructed i can get both cpu and ram to run at 133 then overclock to what i would like....(hopefully 165)

thanks a lot for current advice i am currently in ordering RAM on ur say so and would just like to confirm whether i should buy ddr400 or ddr333 thers hardly any difference in price...

please advise further....

also do u have any idea of speeds i will be able to acheive??

Thanks people and espeically JAM.

Check your manual & see if there's a jumper on the board that selects your "base" FSB...100/133/166. I'll do a quick search & see what I can come up with, but I'm almost certain that you have other FSB settings from 166-200mhz.

I'm wondering if there are different versions of this board or if a more recent BIOS would give you higher FSB options, because I've run across several review sites that mention a max FSB of 200mhz & 1mhz incremental settings from 166-200mhz?

my model was the first flagship for gigabyte it was gigabyte ga-7vrxp the one with 200fsb is the ga-7vaxp it is a completely newer motherboard.

Alsoi have one of the earliest examples of this motherboard as i was one of the first 50 people to get a hold of one.

jumper setting on mobo itself only allows a change from 100 to 133 everything after that you have to do using the oc feature in the bios,

i have decided to use ddr400 which i might go out and buy tomorrow - last thing i wanted to ask . ...

q1. do you have any rough estimates of the speeds i could achieve??

i have a massive cooling fan at moment my cpu is clocked at 2.1ghz (15X140) - under loads temps go to 45 C maximum....just wanted to know wot sort of speed should i aim to achieve???

thanks again ur a big help - im sure that my setting on my mobo is 133 - 165.

thanks for all.

I'm not gonna take the time to read thru these, but I'll supply you with a few links...see what you can find out...here's a quick clip from the 1st one:

"On the GA-7VRXP based on the AMI BIOS, the settings in BIOS allows you to change the FSB from 100~200Mhz FSB, the Vcore can also be adjusted from the BIOS by +5%,+7.5% and +10%. At 10%, you should be able to reach 1.95v if the default was 1.75v. The CPU multiplier is adjustable through a dip switch as shown in the photo below."

http://www.ocworkbench.com/2002/gigabyte/7vrxp/7vrxpp1.htm

http://www.tweaktown.com/document.php?dType=review&dId=211

http://www.itreviews.co.uk/hardware/h302.htm

i hear wot you are saying but as far as i can see from my mobo bios and my manual i can only go to 165....its reeally weird though..

i do know that these motherboards came out in revolutions - it could be the last ones (rev 2.0) were able to work with bus of 200.

one thing dont u think its weird if a mobo is capable of 400fsb - then y is the memory for it only allowed to go 333???? i find this extremely weird maybe people have accidently misquoted the mobo's capabilities?

thanks for links i had seen the last two prior to ur info the first one is still puzzling me......

oh yes nd im using the latest bios as far as i know - F12...

cheers for advice and help

hey u r correct - i can change it up until 200mhz - sorry for trouble about that - amazing - well im definetly getting some ddr400 ram tomorrow along with some cryogenic cooling to cool down my pc ;Op - hehehe thanks again everyhing solved -

will let everyone know how i get on.

Hi Jav I have the same board as you its a
ga-7vrxp ver1.1 and I use f7 bios, had same
prob as you trying to overclock it, my system
has pc2100 ram so I thought that was the
problem, but I did a bit of bios tweaking and
found that if I changed Fast Command to
(Normal) in Chipset Features I could get my
xp1600 up to xp1800, before I did this system
would only go upto 140 fsb and this was
unstable..