CPU critical temperatures and voltage

Peezee · *Last edited by Peezee; 05-01-2008 at 16:05.*

I have a Pentium 4 Prescott 3.2GHz.

I feel like overclocking it, so my 8800GT won't be as bottlenecked. But I don't wanna waste money on a new cooler for it - I'll be getting a completely new CPU in about a month.

Currently, my CPU idles at about 45C, and it hits just about 60C under load.
How many degrees can the CPU take before it gets too much? I really am more of a graphics card person, I haven't ever overclocked my CPU, even though I know exactly how.
And on a different note, how much can I up the voltage of this CPU before frying it? How much is safe?

Cheers,
Peezee.

Hey Mario® · 05-01-2008, 14:10 | posts: 73

I don't think overclocking a Prescott will help a 8800GT much.
It's not worth it in my opinion, even less if you're hitting high temps.

But if you want a number, 80ºC would be the top for me.
From what I know, a friend of mine was running his at 3.4 GHz @ 79ºC. And I don't think you could gain much performance with that.

Peezee · 05-01-2008, 14:28 | posts: 2,617 | Location: Denmark

Was he using stock cooler?
And of course, any improvement on CPU will loosen the bottleneck a bit. I'm doing it for the sake of my GPU, and I don't wanna torture it more than I have to this upcoming month

Any small improvement will help, with such a lame processor...

Should I up the voltage if I overclock it a bit?

Hey Mario® · 05-01-2008, 14:52 | posts: 73

Yes, he had a stock cooler.

And if you want to overclock you just need to play around with the settings (assuming you already know what to do) and see if it is stable.

Maybe you can get better results. I've heard of 230x16 (3680 MHz) with 1.6v and a stock cooler. But I don't know if it can be pushed like that for everyday use.
AND don't go that high the first time, see how it goes @ 3.4, then 3.5 and finally 3.6 if possible.

And by the way, what CPU are you getting?

Peezee · 05-01-2008, 14:55 | posts: 2,617 | Location: Denmark

Getting an E8400 or Q6600, haven't decided yet.
Depends which one is most future proof. Even though the Q6600 is older technology, I guess it may be it - 4 cores and 8 threads... Will be used much more in upcoming games.

proFits · 05-01-2008, 15:02 | posts: 5,749 | Location: Montreal

Quote:

Originally Posted by Peezee

Getting an E8400 or Q6600, haven't decided yet.
Depends which one is most future proof. Even though the Q6600 is older technology, I guess it may be it - 4 cores and 8 threads... Will be used much more in upcoming games.

The dual is good but as time goes by the better it is to buy quad core, even tho the main PC release of 2008 are still to come

Either that or you have the patience for nehalem

Peezee · 05-01-2008, 15:19 | posts: 2,617 | Location: Denmark

Nehalem? No thanks.

It's gonna require a new motherboard with a new socket to run. And there will be two different types - low/mid-range will run on one socket, high-end will run on another.

It's downright stupid. And months will pass till it's out, I wouldn't bet on anything before August.

Peezee · *Last edited by Peezee; 05-01-2008 at 16:17.*

I do not currently own the Gigabyte GA-P35-DS3L, I have ordered it and it will arrive tomorrow.
I just tried overclocking my CPU with my current ASRock 4CoreDual-SATA2. At 3.42, I cannot boot up Windows. So it's now set to 3.34 GHz. I cannot clock it any higher, because apparently my current crap board cannot set CPU voltages. Lame, I know. And I know that I couldn't boot due to voltage problems, I'm sure of that. I'm running 48C idle now with 3.34GHz, and with Prime95, my max load temperature seems to be 63C...

Is Prime95 a good option for testing stability of a CPU overclock?

EDIT: Tried Orthos. Max load is 64C at 3.34GHz. When I receive my Gigabyte GA-P35-DS3L tomorrow (which has the ability to up the voltages), I will go for a clock of 3.45 to 3.5 or so. I'm sure the only reason it couldn't clock more is because of voltage problems, for 64C isn't critical. That was with Orthos, CPU at 100% for 15 mins.

Hey Mario® · 05-01-2008, 16:14 | posts: 73

Yep

And maybe your RAM is holding back your overclock...

Peezee · 05-01-2008, 16:20 | posts: 2,617 | Location: Denmark

You think my RAM could be holding it back?
How? It's only 667MHz RAM.

I am new to overclocking CPUs, and don't really see what RAM has to do with it. Probably some FSB stuff? Please explain

I would have thought the inability to increase CPU voltage was the sinner, but perhaps not?

Hey Mario® · 05-01-2008, 16:32 | posts: 73

Yes, when you raise the FSB you are modifying CPU, RAM and PCI. Unless you can raise everything but your RAM with that MOBO, it will be holding you back. That's why you have better chances of overclocking with 800/1066/1333MHz DDR2 RAM.

Peezee · 05-01-2008, 16:36 | posts: 2,617 | Location: Denmark

Quote:

Originally Posted by Hey Mario®

Yes, when you raise the FSB you are modifying CPU, RAM and PCI. Unless you can raise everything but your RAM with that MOBO, it will be holding you back. That's why you have better chances of overclocking with 800/1066/1333MHz DDR2 RAM.

Why would RAM with a higher clock speed overclock better? I don't get it.
Since the P4 has such a high multiplier of 16, I'm also wondering whether I've raised RAM speed by raising FSB by this petty amount of 9 MHz?

Hey Mario® · 05-01-2008, 16:49 | posts: 73

FSB x Memory Multiplier = DDR Frequency.
Examples:
266 x 2 = DDR2-533
266 x 2.5 = DDR2-665
400 x 2 = DDR2-800
400 x 2.5 = DDR2-1000

If you have a DDR2-533 memory and raise the FSB to 400MHz, they would be working (in theory) at the same frequency than DDR2-800MHz. But it is unlikely that they would reach that frequency.

The memory would be responsible of holding back the FSB.
If you don't push it enough to it's limits, then it's not the memory. It depends on your overclocking.

EDIT: If you're planning overclocking your new CPU, then I'm sure you'll be limited by your memory to certain frequency. And you'd get better results with DDR2-800 or 1066

Peezee · 05-01-2008, 16:57 | posts: 2,617 | Location: Denmark

So for what reason would DDR2-800 clock better? Because it has a lower multiplier?

Hey Mario® · 05-01-2008, 17:12 | posts: 73

When you start raising the FSB, the memory frequency raises as well. If the memory frequency is lower, it'll find it's limit before a higher frequency memory. Because the FSB will push it.
So for example, I can reach 4.2 GHz with my memory (467x9=934MHz). I'm overclocking my RAM there. And if I get to 4.3 I'll start having crashes etc because my memory is working too fast, just like the CPU when its too overclocked. If I go even further I couldn't even boot. But if I had 1066MHz, I could get to that same frequency without any problems (if the CPU or any other thing isn't a problem).

EDIT: crap, sorry for the mistake.
467x9 = 4203 MHz on the CPU.
But 467x2(memory) = 934MHz.

Peezee · 05-01-2008, 17:15 | posts: 2,617 | Location: Denmark

So the higher the RAM speed is, the more potential for overclocking, because it's made for much higher speeds to begin with? In short...

Peezee · 05-01-2008, 17:21 | posts: 2,617 | Location: Denmark

That made me think. On CPUs that doesn't have a locked multiplier, what would happen if I raise that?

Cause, if I cannot raise FSB alot (or would I be able to raise FSB more with an E8400 than with a P4, for an example? I can only keep it stable with an increment of 7 MHz on the FSB with the P4), then I could at least try ratio, right? For an example, with a C2D... That way it could be nicely clocked without the risk of frying my RAM >_>

Hey Mario® · 05-01-2008, 17:21 | posts: 73

Yes

EDIT: the E8400 doesn't have unlocked multiplier, its capped at 9x. The E8500 at 9.5x I think, and the extreme editions are unlocked.

Peezee · 05-01-2008, 17:39 | posts: 2,617 | Location: Denmark

So I won't be able to overclock the E8400 to more than, say, 3.2 with my current RAM?
I got stability issues with RAM running at 694 or so, but none at 690... So I could only increase my FSB by 7 MHz, thus giving me 3.31GHz.

Also, you said "FSB x Memory Multiplier = DDR Frequency."
But my FSB is at 207, yet my memory must be at more, since it's DDR2-667. After all, you said that 665 (I take it that's the same) has an FSB of 266 times 2.5...

WaroDaBeast · 05-01-2008, 18:00 | posts: 1,867 | Location: Réunion

On a side note, a Prescott 3.2's max temperature is about 67 - 69°C, depending on the model.

Hey Mario® · 05-01-2008, 18:08 | posts: 73

Quote:

Originally Posted by Peezee

So I won't be able to overclock the E8400 to more than, say, 3.2 with my current RAM?
I got stability issues with RAM running at 694 or so, but none at 690... So I could only increase my FSB by 7 MHz, thus giving me 3.31GHz.

Also, you said "FSB x Memory Multiplier = DDR Frequency."
But my FSB is at 207, yet my memory must be at more, since it's DDR2-667. After all, you said that 665 (I take it that's the same) has an FSB of 266 times 2.5...

That would be when overclocking.

If you have 667 on the RAM (333x2), a E8400 would be fine (333x9).
But overclocking is an issue.
If you had 800 MHz, you'd need to go past 400MHz to start rising the RAM.

Peezee · *Last edited by Peezee; 05-01-2008 at 18:30.*

So if the FSB speed on the processor is above or the same as the FSB speed on the RAM, it will not raise it?
You're not explaining very well, you are just giving examples without explaining the fundamentals behind it. ;/

EDIT:

Quote:

If you had 800 MHz, you'd need to go past 400MHz to start rising the RAM.

This I do not understand. So if the FSB rises above the FSB speed on the RAM, it would start raising it? And it would not if below?
That would not make sense. Because if I raise the speed on my CPU (standard is 200MHz FSB), my RAM speed rises too. But my RAM has 333MHz FSB?

Hey Mario® · 05-01-2008, 18:49 | posts: 73

If the FSB MHz runs faster than the memory MHz, it will raise it.
If the FSB MHz runs slower that its default configuration, it will lower the memory MHz.
Then, depending on the motherboard, you can lower each independently. So that the FSB raises and the memory stays at a lower frequency, or the memory is overclocked and the FSB stays the same.
So if the FSB MHz doesn't go above the memory MHz, it won't modify it.
If it does, then the memory stays at the same frequency as the FSB, that's the problem with slow memory. If it isn't fast enough, it can't keep with overclocking.

So if you rise the FSB above the RAM MHz, it will rise it.
Like: 333MHz FSB = 400x2=800MHz of memory.
399MHz FSB = 400x2=800MHz of memory.
401MHz FSB = 401x2=802MHz of memory.

Sorry if I can't be clear enough, I'm well know for explaining things like an a$$...

Passion Fruit · 05-01-2008, 19:05 | posts: 5,830 | Location: Middlesbrough, England

Ill see if i can explain a little better.

The RAM doesnt have A FSB.

The RAM and the FSB are linked, so whenever you increase the FSB (to overclock the CPU) you're also overclocking your RAM.

So for example if you buy a MOBO and a CPU that have a FSB of 1066 but you only buy 667Mhz Ram, the RAM will be the bottleneck on your overclock because it won't be able to run as fast as the FSB.

So if you buy a 1066 Board + Mobo with 1066Mhz RAM, you'll be able to atain good overclocks, while maintaining a 1:1 ratio with the FSB (ballistix are good upto 1200mhz) or you could increase the FSB further and lower the ratio on the ram to keep that closer to 1066 while pumping up the FSB.

Arctucas · 05-01-2008, 19:21 | posts: 1,749

@Peezee,

If you want to learn about RAM, here is a pretty good guide:
http://forums.extremeoverclocking.com/t286158.html