C2Q Q6600 or Q8400?

[blackroseMD1]

OK...so right now I am currently running the Core 2 Quad Q8400 at 2.66Ghz. In a machine that I have in the closet, I have a Q6600 @ 2.4Ghz. I know that I can OC the 6600 to a little over 3 Ghz on stock cooling, no problem. I tried to OC the 8400 up to 3 the other day and got a bios error about a 333Mhz processor being installed and then forced to reboot back into the bios.

My question is: Should I throw the 6600 back in here, or should I stick with the 8400? The question is in terms of which I would get the best performance out of.

My mobo and other specs are listed below.

 

[nate42nd]

I wonder if the difference is the chip itself or the motherboard, but I have a Q8400 in a Gigabyte EP45-UD3P and it OCs like a champ. I can hit 3Ghz with decent temps (with a Freezer Pro 7) and have had one blue screen trying to push it up to 3.5Ghz. Every PCU is different but i love the Q8400. (I like my i7860 more haha) but I think the Q8400 is a great CPU. I think it's the board or CPU (or cooling) if you're having problems getting a stable 3.0

All that said, the 6600 is one of the best for a good reason, but performance would go to the Q8400 all things equal I believe.

 

[blackroseMD1]

Thanks for the reply nate. Yeah, I'm guessing it probably is the mobo, as that was the first time I had attempted to OC since building this new rig. I'm thinking I will stick with the 8400, and just see if I can find some settings in the bios that will allow me to OC it a bit.

 

[nate42nd]

Thanks for the reply nate. Yeah, I'm guessing it probably is the mobo, as that was the first time I had attempted to OC since building this new rig. I'm thinking I will stick with the 8400, and just see if I can find some settings in the bios that will allow me to OC it a bit.

I do like the Q8400....you already know this I'm sure but you might see if there's a BIOS update for the board. Sometimes they add OCing features. You could always spend $120 and get a EP45-UD3P too. I have never loved a board as much as this one.

All the best.

 

[pparks1]

Performance might be tricky to figure out here. As you can see in this chart, Intel® Core™2 Quad Processor - Specifications

The Q6600 has 8MB of L2 cache...while the Q8400 only has 4MB of L2 cache.

The Q8400 runs on a 1333Mhz FSB, so a 333Mhz bus quad pumped
The Q6600 runs on a 1066Mhz FSB, so a 267Mhz bus quad pumped

So, it all depends on which you take more advantage of...the additional L2 cache or the faster bus and memory speeds possible.

When I did my build, I went with the Q9550 to get the 12MB of L2 cache and the 1333Mhz FSB. And I have been quite happy with that CPU. On my GA-EP45-UD3R 1.1 rev mobo, I'm running that 2.83ghz at 3.20 on the stock air cooler with no heat issues at all.

 

[blackroseMD1]

Well, I updated the bios, bumped up the voltages a notch, and have it set on 2.8 for now. Gonna check the temps in a bit and then see about reaching 3.0.

Weird thing was, updating the bios seemed to wipe almost all of the drivers from my sytem.

Edit: Nope...seems like 2.8 is as far as I can push it.

 

[Everlong]

You can only push it from 2.6 to 2.8? There must be something wrong, you should be able to get it to 3GHz and over.

 

[blackroseMD1]

I think the problem may be that I haven't bumped the processor voltage any. Anywhere between 2.85 and 3 and it would blue screen right away.

Think I could get it higher if I boosted the processor voltage?

 

[nate42nd]

You also must remember 45nm CPUs react differently from 65nm (like the Q6600) to OCing

The 45nm CPUs (like the Q8400) are a little different to OC. If you usee the exact same methods as 65nm CPUs you will not get the best results.

Read up on OCing the 45nm chips. I find them easy to OC but they are not the same as 65nm.

 

[nate42nd]

I think the problem may be that I haven't bumped the processor voltage any. Anywhere between 2.85 and 3 and it would blue screen right away.

Think I could get it higher if I boosted the processor voltage?

Yes, and the 45nm CPUs like a small bump in CPU termination voltage to (not sure if that option is on your board) I had a lot more luck when I bumped that a bit.

Also, I know people will have mixed reactions to this but I have found this to be a pretty good "general" guide on how well CPUs perform. They have good lists on cards and hard drives too.

http://www.cpubenchmark.net/high_end_cpus.html

 

[Wishmaster]

i know nothing about your board or bios but:

8GB RAM is going to make it a much more difficult to OC.

Im guessing you have 4x2GB sticks of RAM?

Once you start OCing the CPU will take a bit more Vcore, and the NB will def. need some extra juice to hold the load stable,
much sooner than you noramlly would with just 2sticks.

Have you tried upping the NB voltage a bit?
May very well take just a little extra vcore too, but im guessing NB may be an issue

 

[blackroseMD1]

I've bumped the NB up to the next level up, which I believe was 1.6. I may try upping it a bit more. Yeah, I do have 4x2GB installed.

 

[Everlong]

If it blue screens that early then increasing the voltage by 1 or 2 increments should give you a bit more headroom. If you are wanting to overclock then 3GHz is a good round number to hit. I managed to get my old E8200 to 3GHz without problems.

 

[blackroseMD1]

Nope...even increasing both the NB and Vcore, if I push it up even to 2.8, it eventually bluescreens. I think I'm just going to leave it at default and throw an i7 in here when I get my tax return.

 

[Wishmaster]

Wonder if its the memory bombing out on you and not so much the CPU. That CPU should OC a bit more fairly easily.
Might take a bit of experementing to find whats holding you back.

Couple suggestions if you wish to try:
Try dropping the RAM speed to1066 speeds and start OCing from there, or have you tried this already?
You could also try with 2 sticks of RAM, just to see what results you get.

It may not be the CPU or the RAM thats having issues rather the MOBO itself simply doesnt like running any faster FSB speeds with all 4 DIMMS populated.
Some are like that sadly.
Trying w/just 2 sticks in can answer that question though.

 

[blackroseMD1]

Yeah, I'm starting to think it is the mobo. I plan on getting a new one with my tax money anyway, as I want one that supports SLI. I figure I'll just hold out on the OCing until then, as it's only a couple weeks away.