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I5 750 Heat issue

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September 19, 2009 6:49:10 PM

Just finished assembling a i5 750 build and was looking to overclock...

When I did a stress test using Prime95, the temperatures ran too hot at stock 2.66ghz (133mhz bus) ... it achieved 90+ C after only about 22% of the heat up phase on Prime95 (~2minutes)

Could this be an assembly issue?

I'm using Antec 300 case with their stock fans, the intel supplied Heatsync, the GPU fan, and the PSU fan are the fans that current exist inside the machine. No aftermarket cooler...

GPU: HD4870 ATI 1GB

Thanks!

More about : 750 heat issue

September 19, 2009 7:19:08 PM

if those temps are accurate they are way to high for stock....you need to make sure the cooler is making good contact. I would completely remove it and start over. Did you make sure the fan was working on the heatsink?
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September 19, 2009 7:49:28 PM

Yes, temps too high. if the fan isn't workin, the mobo should just shut down unless you disabled that control.

Unless you left the plastic cover on the heatsink when you installed it, or removed the pre-applied thermal paste, the heatsink is not properly seated on the mobo.

You need to remove the mobo and make sure that each of the four legs shows two white pins poking through the back of the mobo, with a black pin in between them. And that the barbs on the white pins grasp the back of the mobo, locking that leg in place.
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September 19, 2009 9:18:07 PM

I resat my heatsync and reapplied thermal compound...
I also rewired my case so the wires were far away from the fans...

I reran the stress test, and it seemed to stabilize right at 88 C...

This still seems excessively high...

Should I just get an aftermarket cooler? Or does the problem exist elsewhere?

Another question:

What's the acceptable stable heat levels for the i5 750?
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September 19, 2009 10:14:35 PM

Rije159 said:
What's the acceptable stable heat levels for the i5 750?

From Intel's Processor Spec Finder - http://processorfinder.intel.com/details.aspx?sSpec=SLB...

Vcore Max 1.4v
Tcase Max (CPU temperature) 73c
Tjunction (Core temperature) 78c

From the Core i7 and Core 2 Temperature Guide - http://www.tomshardware.com/forum/221745-29-sticky-core...


Section 1: Introduction

Core i and Core 2 processors have 2 different types of temperature sensors; a CPU case (not computer case) Thermal Diode centered under the Cores, and Digital Thermal Sensors located on each Core. The case Thermal Diode measures Tcase (Temperature case), which is CPU temperature, and the Digital Thermal Sensors measure Tjunction (Temperature junction), which is Core temperature. Since these sensors measure 2 distinct thermal levels, there is a 5c temperature difference between them, which is Tcase to Tjunction Gradient. Core i7’s / i5’s and Core 2 Quad’s have 1 Tcase and 4 Tjunction sensors, while Core 2 Duo's have 1 Tcase and 2 Tjunction sensors ...

... The monitoring utilities provided by motherboard manufacturers monitor CPU temperature, while some popular freeware utilities monitor Core temperatures ... Real Temp ... is recommended for users interested in monitoring Core temperatures only ... SpeedFan monitors Tcase (CPU temperature) and Tjunction (Core temperature) ...


The thermal specification which is shown in Intel's Processor Spec Finder is Tcase Max (CPU) NOT Tjunction (Core), which is a very common misconception among most enthusiasts. Since there's a 5c gradient between the CPU sensor and the Core sensors, (shown in the following Intel document) - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf - just add 5c to the value shown in the Spec Finder to find the corresponding Core temperature, which is 78c for the Core i5 750.

Intel's second and frequently misunderstood thermal specification, Tjunction Max, (100c for all Core i variants) applies to overtemp protection such as Throttle and Shutdown, so you don't toast your transistors. As such, any i5 Core temperatures which exceed 78c should be considered "overtemp". Further, when specifications are exceeded, then premature processor degradation (longevity) becomes a factor that should be considered, which is explained in the following AnandTech article - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3...

Hope this helps,

Comp :sol: 
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September 19, 2009 10:24:06 PM

Thanks a lot for the information!

So the reason for such excessively high temps at 2.66 stock clock would be the case's air intake? Just the case's quality would cause the processor to be unstable at manufacturing specs?

It almost feels to me like the Heatsync isn't doing its job...
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September 19, 2009 10:28:31 PM

I can confirm that the temps on this chip are very high. and I've also re-pasted. After playing GTA for 5 mis with a stock cooler the temps hit 83c so I shut the game down. It's housed in a new CM 690 with 5 x 120mm fans and a mobo temp of 27c.

I ordered a Zalman CNPS10X to go with my Asus P7P55D Pro, but the 1156 bracket that Zalman made doesn't fit the mobo, so I RMA'd it. I'm less than impressed with them and the cooling manufacturers in general as they are dragging their feet in releasing new coolers and brackets. So I have a shiny new PC bought for gaming which I can do nothing with apart from basic tasks.

On the review in the link they comment how small and thin the stock cooler is.

http://www.legitreviews.com/article/1060/5/



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September 19, 2009 11:13:56 PM

I reseated the heatsync and thermal compound one more time....

Apparently the connection wasn't making full contact....
This fixed my problem... Stock clock prime95 temps are maxing at about 67 C
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September 19, 2009 11:24:41 PM

Damned push pins. Good job.

Don't use "Blend" as it's a memory test that cycles at less than 100% workload during certain test segments, which yields fluctuating temperatures. Small FFT's instead is a steady-state 100% workload that's ideal for processor thermal testing, which yields steady-state temperatures. Thermal saturation is typically reached within 7 to 8 minutes, so a 10 minute test is adequate.
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September 19, 2009 11:35:06 PM

Thanks for all the help again!

One last plea for advice:

Currently I have the standard Antec 300 case... I know the above poster mentioned a better case...

I can currently reach a 150x20 (21 turbo'd) overclock with max temps at 76 C...

Would it be better to buy another fan for intake on the front of the case or an aftermarket cooler for the CPU to push this OC further?
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September 19, 2009 11:41:39 PM

By all means, your highest priority should be a better CPU cooler, which combined with meticulous cable management, will do more to lower your temperatures than adding another case fan.
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September 19, 2009 11:57:44 PM

Rije159 said:
I reseated the heatsync and thermal compound one more time....

Apparently the connection wasn't making full contact....
This fixed my problem... Stock clock prime95 temps are maxing at about 67 C



me too and now after 5 mins GTA is running at 57c :) 

Thanks for all your help guys I was fairly pissed off at not being able to play GTA. I'm just cracking a beer for a long sesson :) 
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September 20, 2009 2:11:52 AM

Rije159 said:
Thanks for all the help again!

One last plea for advice:

Currently I have the standard Antec 300 case... I know the above poster mentioned a better case...

I can currently reach a 150x20 (21 turbo'd) overclock with max temps at 76 C...

Would it be better to buy another fan for intake on the front of the case or an aftermarket cooler for the CPU to push this OC further?

Looking at Newegg, the standard Antec 300 comes with two front intake, one top exhaust, and one rear exhaust fan. That's plenty. Make sure your wiring does not restrict air flow any more than necessary, and that's pretty much the best that case is going to do.

If you do not have those 4 fans installed, by all means install them.

If you are going to do *any* 24/7 OC, you should install a high-performing aftermarket cooler.
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September 20, 2009 3:36:26 AM

You're probably correct - but 4 fans in that arrangement is plenty for that case. More isn't going to help.

A side fan will create backpressure, and there's no room for other fans in the flow.
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September 20, 2009 7:14:52 AM

the standard 300 only had a rear and top exhaust fan. the 300 illusion comes with two front 120mm intake fans. if he only has the 300, he doesn't actually have any intake fans at all.
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September 20, 2009 7:16:51 AM

Then I fall back on what I said earlier . . . if you don't have those four fans, by all means install them.
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September 20, 2009 8:35:24 PM

Ask Gary at Sidewinder when they will be stocking
an LGA1156 bolt-thru-kit.

Meanwhile, read and heed:

http://www.supremelaw.org/systems/heatsinks/warning.htm

http://www.sidewindercomputers.com/lgbowiscsp.html

http://www.sidewindercomputers.com/lga13sobbowi.html


Intel changed the hole positions for the fasteners,
so neither of the above will work with the LGA1156 socket:

http://www.eteknix.com/previews/asus-p7p55d-evo-lga-115...

Unfortunately Intel have decided that it would be a good idea to have another change in HSF mounting hole positions, which Asus can do nothing about. So current 1366 coolers and even 775 coolers will be incompatible, so it really is a completely new setup and we really have to ask, why!? It is possible that Intel have improved the mounting system on their retail coolers for the lower end i5 and i7 models which requires different hole locations. We do however feel that its much more likely that they’ve saved money by producing cheaper HSFs for a range of processors where the heat output will be lower than the current Bloomfield i7s, keeping the more expensive high end HSFs for the higher end chips, but this of course is all speculation and I expect we will never know what Intel were thinking (or not) when they made this decision. What this means for most of us is that we can’t use the current crop of aftermarket i7 coolers designed for 1366 motherboards, many of which are frankly excellent. Hopefully the hard done by HSF manufacturers are on to this issue already and there will be 1156 coolers & adapter kits for some of the great 1366 coolers already on the market, before the release of Intel’s new 1156 boards and CPUs.

[end quote]


There IS something ASUS can do about it: they can manufacture
2 sets of holes, as they have done with other motherboards
like the P6T:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
(use "image viewer")


MRFS
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