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Temp and Cooling questions

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November 5, 2009 11:40:46 PM

Hi, I have a few questions concerning my comp's temp, here's my rig's specs:

Case: Rosewill Conqueror RPS-01-WB500P
http://www.newegg.com/Product/.....6811147118

Mobo: ASUS P7P55D LGA 1156 Intel P55 ATX Intel Motherboard
http://www.newegg.com/Product/.....6813131404

CPU: Intel Core i5-750 Lynnfield 2.66GHz 8MB L3 Cache LGA 1156 95W Quad-Core Processor
http://www.newegg.com/Product/.....6819115215

RAM: CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMX4GX3M2A1600C9
http://www.newegg.com/Product/.....6820145260

HDD: Western Digital Caviar Green WD10EADS 1TB 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive
http://www.newegg.com/Product/.....6822136317

Video Card: ASUS EAH4890/HTDI/1GD5 Radeon HD 4890 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card
http://www.newegg.com/Product/.....6814121308

PSU: Antec EarthWatts EA750 750W Continuous Power ATX12V version 2.3 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC
http://www.newegg.com/Product/.....6817371026


Ok so I built this rig recently, and downloaded Speedfan to monitor my hardware's temp. I also downloaded Prime95 to test my cooling.

It runs at around 46c when idle, and around 70c when playing World of Warcraft. I tried running a torture test with Prime95 but I stopped it after a couple minutes b/c the CPU started reaching temps of 85c+

My questions are:

What is the maximum safe operating temperature for this rig, under load?
Is my cooling sufficient, or should I buy water cooling?

More about : temp cooling questions

Best solution

a b K Overclocking
November 6, 2009 12:28:46 AM

1. There is NO NEED for WCing for you (unless you are an high OCer). WCing done right will cost you $250-300 for just the CPU.

2. SpeedFan (unless calibrated) can be off by as much as 15C.

3. As for the CPU, Intel says not above 73C (Tj not TjMax). http://processorfinder.intel.com/details.aspx?sSpec=SLB...

My recommendations:

1. Try re-seating cooler, re applying paste etc.

2. Buy a good air cooler. Any of the top 10 listed here should work well: http://www.frostytech.com/top5heatsinks.cfm
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November 6, 2009 1:11:05 AM

Could you tell me how to properly calibrate it? I'm afraid to touch any settings, since I know certain things can mess up your computer.
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a b K Overclocking
November 6, 2009 2:38:45 AM

Just download CoreTemp and your all set, OH and YES buy a better cooler.
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November 6, 2009 4:44:39 AM

Core temp is giving me the same readings as Speedfan is. Is it accurate? I tries using realtemp but I get BSoD every time I try to run it.
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a b K Overclocking
November 9, 2009 9:27:09 PM

TMP555 said:
... Core i5-750 ... Prime95 ... temps of 85c+

What is the maximum safe operating temperature for this rig, under load?
Is my cooling sufficient, or should I buy water cooling?
TMP555 said:
Core temp is giving me the same readings as Speedfan is. Is it accurate?
TMP555,

In your circumstance, SpeedFan is just as accurate as Real Temp or Core Temp, and yes, you definately need better cooling, but not necessarily liquid cooling. High-end air cooling will be fine, especially since the i5 750 doesn't have HyperThreading. Regardless, the stock cooler is woefully inadequate, so before you get your new cooler, here's what you need to know.

Temperatures and overclocking are all about specifications, so it's very important to be specific. If we're not, then the topic makes about as much sense as comparing apples-to-oranges thermal fruit salad in a blender! :pt1cable:  My objective is to assure that enthusiasts understand Intel's specifications, standards and test methods, so they can better decide how to apply and manage their overclocking options.

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

Core i5 750:

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 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 determine the corresponding Core temperature, which is 78c for the Core i5 750.

Intel's second and frequently misunderstood Thermal Specification, Tjunction Max, (100c for the Core i5 750) applies to overtemp protection such as Throttle and Shutdown, so you don't toast your transistors. As such, any i5 750 Core temperatures which exceed 78c should be considered "overtemp". Further, when specifications are exceeded, then processor degradation becomes a concern, which is explained in the following AnandTech article - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3...

Prime95 Small FFT's is the Standard for processor thermal testing, because it's a steady-state 100% workload which yields steady-state temperatures, whereas Blend is a memory cyclic workload which yields fluctuating processor temperatures. Small FFT's will reach 97% thermal saturation within 7 to 8 minutes, so a 10 minute test is adequate. Thermal testing should be conducted as close as possible to 22c (72f) Standard ambient, with case covers removed, the computer clear of any desk enclosures, and all fans at 100% RPM to eliminate cooling variables, and to produce consistent and repeatable results for comparisons. If the Gradient between CPU temperature and "mean" (average) Core temperature is not ~ 5c, then BIOS is incorrectly coded. CPU temperature and Core temperatures can be individually calibrated in SpeedFan by following the Calibrations Section in the Temperature Guide.

OCCT and Burn Test use LinPack, which shows thermal signatures that resemble the ups and downs of a bad day on the stock market, and cycle between light workloads, through test segments which spray all processor registers with all one's, (100% thermal load = 115% workload), and can push an overclocked i5 750 at Vcore Max 1.4, right on past Tcase Max! :o 

Since there are very few applications or games that will spike, let alone sustain processor workloads beyond 70% to 85%, utilities which load all registers with all one's are not representative of real-world computing. While these utilities are certainly very useful for stability testing, they are inappropriate for thermal testing. The 3DMark benches are excellent for stability testing, as are applications for ripping and encoding.

To make sense of CPU temperature and Core temperature, compare them to a 4 cylinder car with 5 temperature guages; 4 of the guages are cyclinder head temperatures (closest to the heat source), and the 5th guage is the overall engine temperature, which is 5c lower than the other guages, and is the temperature guage with which we're all familiar. We know the red zone (hot) for the i5 750 starts at 68c (Tcase Max) on the engine temp guage and 73c (Tjunction) on the cylinder head temp guages, but if we push the engine too hard and peg all the guages, (95c Tcase overtemp / 100c Tjunction Max) then the engine will shut down.

If you'd like to learn more about processor temperatures, then just click on the link in my signature.

Hope this helps,

Comp :sol: 



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November 10, 2009 5:04:37 AM

Thanks for the reply Computronix. The thing is, I actually haven't overclocked at all yet. (Although on second thought I have installed and use TurboV Evo) Assuming SpeedFan is accurate and does not need calibration, my CPU hits around 70-73 while playing World of Warcraft. I won't get paid until next week to buy a better air cooler, so is this still safe? There are also times where SpeedFan reads upwards of 75-76C.

Oh also, while SpeedFan is reporting CPU Temps of 70c+ in WoW, the cores themselves read a temp 15-20c below it at all times, so if the CPU is burning at 70c, the cores are each reading at 55-60c. Which temp should I consider when worrying about my processor's temp?

Another question, I was told that generally more expensive/higher grade thermal paste helps alot rather than using stock paste, so I bought Arctic Silver and put that on, is it better than most?
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a b K Overclocking
November 10, 2009 1:24:52 PM

TMP555 said:
... while SpeedFan is reporting CPU Temps of 70c+ in WoW, the cores themselves read a temp 15-20c below it at all times, so if the CPU is burning at 70c, the cores are each reading at 55-60c. Which temp should I consider when worrying about my processor's temp?
If you read my post carefully, or if you read my Temperature Guide, then you know that the CPU temperature should be 5c lower than the Core temperatures, which means that your BIOS is miscoded, so SpeedFan needs to be configured for a "minus" offset, which will bring your CPU temperature 5c below the Core temperatures during Prime95 Small FFT's.

TMP555 said:
... Another question, I was told that generally more expensive/higher grade thermal paste helps alot rather than using stock paste, so I bought Arctic Silver and put that on, is it better than most?
I wouldn't exactly characterize it as "alot", so don't expect miracles. In the big picture of processor cooling, I see thermal compound as a second order variable. The difference is typically just 1 to 2c, however, from the best to the worst, the difference can potentially be as much as 3 to 4c.
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November 10, 2009 5:55:57 PM

CompuTronix said:
If you read my post carefully, or if you read my Temperature Guide, then you know that the CPU temperature should be 5c lower than the Core temperatures, which means that your BIOS is miscoded, so SpeedFan needs to be configured for a "minus" offset, which will bring your CPU temperature 5c below the Core temperatures during Prime95 Small FFT's.

I wouldn't exactly characterize it as "alot", so don't expect miracles. In the big picture of processor cooling, I see thermal compound as a second order variable. The difference is typically just 1 to 2c, however, from the best to the worst, the difference can potentially be as much as 3 to 4c.



Thanks so much for all the helpful information. I'm going to try and find a trustworthy thermometer later this week, and hopefully properly calibrate using your guide. Thanks again.
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a b K Overclocking
November 10, 2009 8:36:52 PM

Good luck! :sol: 
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