Overclock Intel 650

[Kantana28]

Ok running on Asus P5GD2 with Zalman 7700 cooler, to get Prime 95 stable need to run Vcore at 1.4375 with 248 FSB. This pushes the Temp to 60 degrees C as reported by PC Probe. If I want to go higher than 248 FSB then need more VCore but once I use 1.45 VCore the temp exceeds 62 degrees C and the TM1 throttling starts. My Zalman is running max at 1800 rpm.
If I want to clock higher than 248 FSB stably what can I do? If I replace the cooler any suggestions for highest performance on air only, don't want to start using water cooling yet.

 

[stevty2889]

I was having issues with my 3.4ghz prescott. It was running at 70c even at default speeds, using a thermalright XP-120. The Zalman 7700 you have is also one of the best possible coolers you could be using. I had to go to water cooling to get mine stable at higher speeds, and I am topped out at 3.91ghz with water cooling. 62c seems to be a low temp for the throttling to be kicking in, mine didn't kick in till 70c, but I have a 550, so maybe they put tighter limits on the 600 series. I would say that your doing really well as it is by hitting 248fsb, that would have your cpu at 4.2ghz...

 

[Kantana28]

The faster the better right? =) Seriously though I can boot into Windows and run other benchmarks at 256 FSB etc but having to raise VCore I wanted a better HSF. 2 x Prime 95 really raises the temp like no other app. 253 will give me 4.3GHz, 259 will give me 4.4 GHz. Just wanted to maximize my OC, also as the winter temps here are about 12 degrees C and the summer temps are about 35 degrees C. Wanted some extra cooling to make sure I'm not crippled in Summer.
62 degrees C is the reading from PC Probe on Asus and Speedfan, as Asus boards normally read lower than actual I would guess this maybe 70 degrees C actual. The thermal limit of the Prescott is specced at 64 degrees C, dunno what the throttling temp is though. Anyone have any ideas or more powerful coolers.

 

[stevty2889]

Well you certainly already got a nice OC out of it. I have had my voltage up as high as 1.525v, but I still can't stay stable past 3.91ghz. The Zalman 7000 is a very good cooler, and I don't think the Thermalright XP-120 is gonna make enough of a differance to bother switching. I don't think your gonna get your temps much lower with any air cooling solution. The themarl spec for my prescott is 71.2c and my throttling kicks in just below that, so your would probably kick in at around 62c.

 

[Kantana28]

OK I'm on a coolermaster hyper 48 now, swapped the default fan with a 9cm Delta fan and running at 1.4875 V and 252 FSB, trying to get Prime 95 stable, the throttling temp reported by the motherboard changes. When I was trying to get stable at 1.4375V and 248 FSB it was 61/62 but now on 1.4875 it is throttling at 57.
Any ideas what's going on?

 

[stevty2889]

Thats normal..when you use a higher Vcore, it sets the throttling temp to a lower temp. You are not likely gonna get a higher stable overclock than you already have with any air cooling solution, and water cooling won't likely get you much higher either, you are very likely at the limits of your chip. There was no air cooling solution what so ever I could use to keep my 3.4ghz LGA775 prescott from throttling at even default, but now I am at 3.91ghz with no throttling.

 

[Duvie]

Originally posted by: stevty2889
I was having issues with my 3.4ghz prescott. It was running at 70c even at default speeds, using a thermalright XP-120. The Zalman 7700 you have is also one of the best possible coolers you could be using. I had to go to water cooling to get mine stable at higher speeds, and I am topped out at 3.91ghz with water cooling. 62c seems to be a low temp for the throttling to be kicking in, mine didn't kick in till 70c, but I have a 550, so maybe they put tighter limits on the 600 series. I would say that your doing really well as it is by hitting 248fsb, that would have your cpu at 4.2ghz...

be careful of not comparing the same chips...he has the 600 series with the new stuff fro thermal throttling....

that is a 3.4ghz chip right??? So 17x multi with a 250fsb is 4.25ghz, right??? What the hell are you complaining about...get water cooling for a setup like that.....You have reached a very high oc with air cooling alone.....

 

[stevty2889]

Which is why I said.."but I have a 550", and used words like maybe..

 

[Duvie]

Originally posted by: stevty2889
Which is why I said.."but I have a 550", and used words like maybe..

Yep I see it....sorry...

Ppl need to realize temps are just hard to compare period.....across platforms...across mobo...etc....


The ineteresting things is as the vcore rises the the throttling point drops eventhough the temps reported are lower...huh.....

What do you guys think this means???

 

[Kantana28]

So I'm stuck at 4.25G? Ireally wanted to reach 4.3G stable in 2x Prime 95, Will upgrading to a XP120 help?

 

[Duvie]

Maybe...but without a clear understanding of what is going on with the drop point of the thermal throttling I wonder if you just need to step up to water to really get anymore.....

As it stands now iI wouild drop to the lower vcore and be happy with 4.2ghz or so.....

I mean wait until summer comes and/or a system that gets a little dust and that 60 to 62c range of safety for thorttling to began is not much of any headroom....You may see significant throttling come this summer....Sadly I think we will see many prescott related threads about this....

 

[Kantana28]

OK currently running 4.25G with 1.45 VCore on 90% Fan power and burning in using 2 x Prime 95 large FFT. The temp at idle was 36 and on 100% load is 54. This should give me some headroom.
Any ideas what the default VCore is for a 650? I read it was 1.4 but some magazines have claimed 1.43. Hoping the CPU will behave with some burning in. The throttling temp boundary dropping with increasing VCore seems very weird unless the Asus motherboards lose accuracy with increasing VCores.
Any other ways to lower temp, I'm already using AS5 with a Delta fan, seems this is the optimum setup with this Cooler Master Hyper 48 heatsink. I want to stay on air cooling rather than water as wary of leaks.
How much difference in degrees does the XP120 with 12cm delta make compared to a stock Zalman 7700 cooler?

 

[Duvie]

I tought it was 1.4v...the interesting thing still is with a minor vcore adjustment like your the Tm1 drop down so low.....you would be on like a 3-4% increase...

have you check to see if that is what actually is being delivered notwhat you are setting in the board bios...Asus's are famous for overvolting so maybe that is higher then you think.....


54-58c is not much headroom considering the swings in temps you will experience come summer....4c in ambient room temp or 7f is minor.....I would say you have no headroom...We have those swings here in Oregon (though maybe not this winter) and that would constitute 8-10c swings for me in my cpu temps...you dont have that room...

 

[Kantana28]

I think I maybe in trouble come summer, I'm in Hong Kong and temp is now 16 degrees. Come summer it will hit 35s! If I continue with this setup at 54 degrees and run all at 100% I don't think I can compensate for a rise in ambient temps of 19 degrees +!
What is the best in air cooling for LGA775 processors, modified or stock? Any way to compensate for a increase in ambient of about 20 degrees? I am running 2 x Antec 12 cm LED fans, if necessary can change these too. My MB temps are 34 on load and about 29 on idle.

 

[stevty2889]

I think the reason the throttling kicks in at a lower temp with a higher Vcore, is due to higher leakage current. The temp is just a calculated measurement by the current going through a diode, rather than a real measurement, so higher voltage, gives higher current, causing the didode to get a higher current, so it detects a higher temp than there really is(just my theory, not sure how accurate it really is). In any case, I couldn't get my throttling to stop until I went to liquid cooling, but I am happy with 3.91ghz.