Overclocking having only FSB control?

I am going to honest, I have an o.e.m. system, please don't throw me out just yet, I understand the difficulties with overclocking o.e.m. systems and their locked BIOS. I am looking for answers more to advance my understanding of overclocking, not to achieve a world record overclock with this system.

Okay, so let me get you up to speed, locked BIOS, overclocking with clockgen by adjusting FSB, this is my only option. System is a Dell (I hesitate to use the D word, that normally gets me thrown out of forums)
E6400 dual core, 1gb of ram ddr2 5300, windows xp 32bit, so far I am at a FSB speed of 308 , 2.45ghz, an 15% overclock according to Everest. I have tried going as high as 2.75ghz, and can except when exiting or entering windows, i get the BSOD. If I adjust while I am in windows, no problems, I can run Prime95 all day long and the temp. stays around 31c and I never get error messages.

So, my question is can you achieve more than a 15% overclock by ONLY adjusting the FSB? I understand that this cpu will go much higher in the right hands, I would love to see 2.6ghz. Could it be my RAM holding me back, for some reason cpuid will not read my ram timings and voltage, I guess it goes back to the locked BIOS. I have 2x1gb of DDR2 SDRAM DDR2 800 (PC2 6400) on order, I needed to upgrade from 1gb any way.

Thank you.

Have you considered a voltmod? Sam just did one on his E6300. http://www.ocforums.com/showthread.php?t=587362

It depends on what she will handle on stock volts. Steven suggested a mobo volt mod I believe. That should get you there if it cant do it on stock volts in teh first place. You can only try!

Some old bum is gonna come in here and say "Back in my day if you wanted a fast celron 300A, FSB was the only thing you could do! We didnt have all those fancy voltage controls and ajustable multipliers...." (I think there were voltage ajustments back then, before someone hijacks a thread over it)

Lol, you should be able to get some out of it before voltage becomes an issue. There are also voltmods you can do and what not. You might not be pushing 4Ghz, but you should be able to get a decent OC out of it yet.

I have been doing some reading on the volt mod but I am not sure my motherboard supports 1333mhz fsb processors. These Dells are funny about stuff like that. I am a little nervous about physically changing anything in the case. At what point is it normally necessary to adjust volts when upping the FSB on a E6400? What are the chances I can increase my FSB more when I swap out the cheap pc 5300 o.e.m. ram for pc 6400 800mhz ram?

Well considering I believe the e6400 is a 266Mhz FSB chip, and your ram is 333Mhz, you have until 333Mhz FSB (2.6Ghz) until you run the ram outside of its specs...

As far as what speed you get before you need voltage...every chip varies, just try it out. When its not prime stable, back off on the o/c a bit until you are stable... Read the guide in my signature. One of the best I found on the net. But you should be able to go to 333Mhz (2.6Ghz) if you made me guess.

Well, I guess I am at the wall. I am at 2.47ghz, FSB @ 308 for a 15% overclock. When I raise the FBS to 309 it locks up. I was expected to be limited more by temp but they have remained unchanged at 30c. There must be some other limiting factor, maybe volts is there any chance the Dell mobo locks out anything over a 15% overclock? It just seems strange that it well work so well right up to 16% overclock?

Can you load cpuZ and post the name of your mobo so we can check whether it supports 1333? It sounds like the volts are probably the issue right now. There is only so much you can overclock before you need more volts.

Idle temps mean nothing. Its the load temps that would be your issue. Run P95 Small FFT and see if that 15% o/c is stable.

I am at work right now, as soon as I get home I will.

I want to thank you guys for offering help and advice! You would be surprised at the boards you are quickly shown the door as soon as you mention Dell! I would have thought overclockers by nature loved a challenge but the responses I have gotten at some sights where anything but,..to hard,.... can't overclock a Dell,.... shouldn't even try.....not very adventurous for a group that likes to take computers places they never have been before. I have went from 2.13ghz to 2.45ghz on my own, and I am a computer idiot! I know it is never going to be a monster overclocker, but hey we all start somewhere.

Thanks again, I will post some more information this afternoon.

Caligula420 said:

Idle temps mean nothing. Its the load temps that would be your issue. Run P95 Small FFT and see if that 15% o/c is stable.

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Yes, I ran Prime95 for several hours and the temp. stayed at 31c. Even with at 2.55ghz (18% over) it never got over 31c. By the way I keep my computer room very cool, around 64F.

Are your using Realtemp to provide your temperatures? That is awfully cool for a full load dual core... in fact that should be around IDLE temps, not load. What are your idle temps? What cooler are you using?

Blazer1 said:

Well, I guess I am at the wall. I am at 2.47ghz, FSB @ 308 for a 15% overclock. When I raise the FBS to 309 it locks up. I was expected to be limited more by temp but they have remained unchanged at 30c. There must be some other limiting factor, maybe volts is there any chance the Dell mobo locks out anything over a 15% overclock? It just seems strange that it well work so well right up to 16% overclock?

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more then likely your stock volts is whats holding you back. the reason the temps dont change much is because ur still on the same stock volts.

you might be able to do a little better with some DDR2 800 ram

Caligula420 said:

Well considering I believe the e6400 is a 266Mhz FSB chip, and your ram is 333Mhz, you have until 333Mhz FSB (2.6Ghz) until you run the ram outside of its specs..

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apintojr said:

you might be able to do a little better with some DDR2 800 ram

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I highly doubt that, see my post above.

I am using Everest for temps. To be honest I don't see much difference in idle to load temps. 28c idle to max ever of 33c load but more often 31c load. Even after many hours of multi-tasking at 2.4ghz the temp will be 31c.

I dont think you are going to be able to go any higher than you already have even with better ram. The reason being is that board will not let you lock the pci to 100. I think you have all you are going to get from that board.

What are your core temps? You're not going to see much different in temps until you start upping the volts

As far as my RAM is concerned I thought that 533mhz ram would only run at 266mhz. FSB speed?

533mhz divided by 2 = 266mhz max FSB speed (1-1)? So at 308mhz FSB I am overclocking my RAM.

Thus, installing 800mhz ram would up my maximum FSB to 400mhz?
I probably need to research this a little more.

PC5400 is 667Mhz. /2= 333Mhz.

It wouldnt up your FSB potential, it would just mean you ram wouldnt run at its rated speed until 400Mhz (on a 1:1 ratio that is).

Your overclocking adventures on this board are done. PCIe lock and voltage are going to limit you.

Caligula420 said:

PC5400 is 667Mhz. /2= 333Mhz.

It wouldnt up your FSB potential, it would just mean you ram wouldnt run at its rated speed until 400Mhz (on a 1:1 ratio that is).

Your overclocking adventures on this board are done. PCIe lock and voltage are going to limit you.

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Fair enough, I am happy with my 15% improvement and what I have learned. Is it possible that my computer has RAM slower than PC5400?