Please comment on my calculations - e6750 OC

[jdmmaster]

Components:

C2D E6750 w/Zalman CNPS9500 cooler

Crucial Tracer DDR2-8500

P5K Motherboard

 

Plan:

1:1 fsb/mem ratio utilizing full 1066Mhz available from ram.

 

What needs to be done:

1) Raise fsb to match memory speed: 1066/2 = 533Mhz

2) Reduce CPU multiplier 8->6 (6 is lowest available) since a crazy overclock is not desired: 6 X 533 = 3198Mhz (3.2Ghz)

3) ?

 

I guess my questions are:

1) Does my logic/math make sense?

2) Am i correct in believing that a 1:1 ratio with RAM is best? (not looking for max Ghz, just max throughput)

3) Before I start the tedious process of slowly raising the fsb, has anyone tried this on this chip? and Vmods/crazy cooling required?

 

All Comments are welcome!!

 

Thanks!

[hardnrg]

I've seen a lot of E6750's around 3.8-4.2 GHz on air... don't cheat yourself out of free speed by not even trying

 

The RAM performance has a small effect on overall performance, so I'd recommend putting your RAM at a slow speed, maybe just 400MHz unlinked, sort your CPU OC out first, then decide how to make that work with the RAM later...

 

1:1 isn't necessarily the best, sometimes high RAM speed is best, sometimes the same RAM can run at a slower-than-max speed at tight timings (e.g. mine, in sig) and get better performance, so just use benchmarks to assess which is actually better since no-one can tell you what is best, you have to find out for yourself

[gotdamojo06]

my personal preference would be to go with a higher cpu clock speed than with memory speed...this is all personal however, you should be able to reach at least 3400MHz (425x8) which will still give you a decent 850MHz mem speed

[Bleeble]

Your calculations seem correct, but I don't know if your mobo/CPU can handle 533 FSB. You'll probably have to raise the chipset voltage to get that high (if it can).

[:[[Deeto]]:]

set your vdimm to 2.3 v if u want ur ram to go 533 mhz... ur proci too will need to raise the vcore... Note : gek proper cooling on proci n memory.. A strong fan would do just fine...

[Bleeble]

set your vdimm to 2.3 v if u want ur ram to go 533 mhz... ur proci too will need to raise the vcore... Note : gek proper cooling on proci n memory.. A strong fan would do just fine...

Not if his RAM is rated to run at lower voltages. :thumbs-up: Just set your RAM to its rated voltages and timings.

[jdmmaster]

Your calculations seem correct, but I don't know if your mobo/CPU can handle 533 FSB. You'll probably have to raise the chipset voltage to get that high (if it can).

 

I think I'll look into better cooling for the mobo before I attempt to raise the voltage, it's already running pretty hot (47*C) at stock settings. I'm thinking of buying a little fan to place on the northbridge fins, hopefully that will suck all the heat out of the heat pipe aswell. The BIOS allows me to adjust the FSB all the way to 800Mhz, but i doubt that will work at the stock voltages.

[Bleeble]

I think I'll look into better cooling for the mobo before I attempt to raise the voltage, it's already running pretty hot (47*C) at stock settings. I'm thinking of buying a little fan to place on the northbridge fins, hopefully that will suck all the heat out of the heat pipe aswell. The BIOS allows me to adjust the FSB all the way to 800Mhz, but i doubt that will work at the stock voltages.

Just because you can set it that high, doesn't mean it'll run that high. If I'm not mistaken, the world record for highest FSB is something like 600-650 right now.

 

Anyway, you really should get active cooling on your chipset and MOSFETs. Mounting a tiny fan on the HS isn't going to accomplish as much as pointing a larger fan in that general direction. Those pathetic little 40mm fans you'd need to get push something like .003 CFM of air, compared to 70+ with a quiet 120mm fan (louder fans will push much more air). OK, slight exaggeration for the small fans, but hopefully you get the point.

[jdmmaster]

Yeah, I have the Antec P180 case, so there are already 3 120mm fans in there

 

But there seems to be an airflow dead spot on the board fins / heat pipe, i think as long as i get a fan moving air across the heat sink it'll be better, the warm air will then quickly get vented by the large fans. I'll try something out this weekend and then start upping the Megahertz

 

So what is stopping people from running a higher speed on the fsb? If the bios supports it, why would the chipset not? I mean with a cpu that can have the multiplier lowered this doesn't seem like a problem?

[Bleeble]

So what is stopping people from running a higher speed on the fsb? If the bios supports it, why would the chipset not? I mean with a cpu that can have the multiplier lowered this doesn't seem like a problem?

The chips (CPU and/or NB) just aren't cable of running beyond a certain speed. If it was simply a matter of voltage and cooling, we'd have Pentium II's running at 5GHz on phase. I'm not an electrical engineer, so I don't know the technical details, but things just can't go beyond a certain point.

 

Think of it like this: if you drop a basketball from a plane, it should theoretically accelerate until the instant it hits the ground, right? Well that's not the case. Once it hits its terminal velocity, it simply can't fall any faster. Before anyone says anything, I know it's not a perfect analogy, but maybe it'll help someone understand. :thumbs-up:

[suchuwato]

If you drop a basketball from a plane, it should theoretically accelerate until the instant it hits the ground, right? Well that's not the case. Once it hits its terminal velocity, it simply can't fall any faster. Before anyone says anything, I know it's not a perfect analogy, but maybe it'll help someone understand. :thumbs-up:

 

That is providing it doesn't burn up...