i7-3820 failing Prime95 at Stock speeds. Is it the CPU, the Motherboard, the RAM, or something else? How do I figure it out? - Overclock.net - An Overclocking Community

Forum Jump: 

i7-3820 failing Prime95 at Stock speeds. Is it the CPU, the Motherboard, the RAM, or something else? How do I figure it out?

Reply
 
Thread Tools
post #1 of 22 (permalink) Old 04-25-2012, 04:41 AM - Thread Starter
New to Overclock.net
 
BuildBuildBuild's Avatar
 
Join Date: Mar 2012
Posts: 28
Rep: 1 (Unique: 1)
About a month ago, I built my first PC:



The original P9X79 Deluxe Motherboard passed over 10 hours of Prime95 @ 3.7 Ghz with the Factory Defaults.

340



I exchanged the Motherboard before overclocking it because it had a faulty temperature sensor as you can see in HWMonitor in the screenshot above.

I've been having difficulty OC'ing the new Motherboard and was only able to get it stable at 4.625 Ghz (9+ hours of Prime95) using a Core Voltage of 1.38v with XMP @ 1600 Mhz:

363



However, I then tested it at stock speeds by resetting the BIOS to "Optimized Defaults", disabling "Turbo mode", and setting the memory to XMP @ 1600 Mhz, and it failed Prime95 in under 7 hours:

363

I'm no expert, but I think this confirms beyond a shadow of a doubt that I have faulty hardware. The question is, what part is faulty and how do I figure it out so I can exchange it? Upon first glance, it would seem it's the Motherboard since the original one passed over 10 hours of Prime95 @ 3.7 Ghz with the Factory Defaults. On the other hand, I've been doing so much tweaking and OC-testing this past week that perhaps I fried the CPU, RAM, or something else.

Please help me figure this out as I am completely out of my depth here and very bummed out. Thanks.


Processor: Intel Core i7-3820 | Motherboard: Asus P9X79 Deluxe | Case: Cooler Master HAF-X | Fan: Noctua NH-D14 SE2011 | RAM: G.Skill Ripjaws Z DDR3 1600 16GB 4x4GB CL7 | HD: Samsung 830 SSD 512 GB | PSU: Seasonic Platinum 860W | Graphics: PowerColor HD 7950 PCS+ 3 GB
BuildBuildBuild is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 04-25-2012, 04:42 AM
New to Overclock.net
 
tahayassen's Avatar
 
Join Date: Feb 2012
Posts: 929
Rep: 31 (Unique: 27)
Definitely the motherboard. CPUs don't just randomly fail like that.

tahayassen is offline  
post #3 of 22 (permalink) Old 04-25-2012, 04:42 AM
New to Overclock.net
 
novemberEcho's Avatar
 
Join Date: Apr 2012
Location: Perth, Western Australia
Posts: 75
Rep: 4 (Unique: 4)
Run a memcheck, could be your ram. CPU would be last option.

Cheers
Zane

novemberEcho is offline  
Sponsored Links
Advertisement
 
post #4 of 22 (permalink) Old 04-25-2012, 04:47 AM
New to Overclock.net
 
Just a nickname's Avatar
 
Join Date: Dec 2009
Posts: 4,184
Rep: 170 (Unique: 130)
optimal default != stock speed.

You failed to mention what is the brand and mobo model. Usually optimal default include a small overclock (extra multi, higher memory bandwidth, etc.)

The motherboard doesn't know if the voltage used is stable or not so they usually overfeed the CPU.

Do you have latest BIOS for the board too? Do not rush and go install a new one. Carefully read and check what is the improvement with newer BIOS.

I would also like to note some boards are crap clocker, it is normal to not have the same overclocking result with different boards.

CPU owned:
i5-750 & EVGA Classified 200 - 4.8GHz
i7-870 & EVGA Classified 200 - 5GHz
i7-2600k & Z77X-UD3H - 5GHz
i7-4790k & MSI Gaming 5 - 5GHz
Just a nickname is offline  
post #5 of 22 (permalink) Old 04-25-2012, 05:36 AM - Thread Starter
New to Overclock.net
 
BuildBuildBuild's Avatar
 
Join Date: Mar 2012
Posts: 28
Rep: 1 (Unique: 1)
Quote:
Originally Posted by tahayassen View Post

Definitely the motherboard. CPUs don't just randomly fail like that.

How can I confirm this?

Quote:
Originally Posted by novemberEcho View Post

Run a memcheck, could be your ram. CPU would be last option.

I had successfully run MemTest for over 12 hours (6 full pases) on the original Motherboard:

379

But maybe the RAM has since fried once I started OC'ing with the new Motherboard, so should I test it again?

Quote:
Originally Posted by Just a nickname View Post

You failed to mention what is the brand and mobo model.

I did mention it and even linked to it, it's the ASUS P9X79 Deluxe.

Quote:
optimal default != stock speed.

Usually optimal default include a small overclock (extra multi, higher memory bandwidth, etc.)

I'm aware of that, that's why I disabled "Turbo mode" to get to Stock speeds. I also mentioned this in my OP.

Quote:
Originally Posted by Just a nickname View Post

The motherboard doesn't know if the voltage used is stable or not so they usually overfeed the CPU.

Do you have latest BIOS for the board too? Do not rush and go install a new one. Carefully read and check what is the improvement with newer BIOS.

I would also like to note some boards are crap clocker, it is normal to not have the same overclocking result with different boards.

I'm using the latest BIOS Version 1103. The original Motherboard was tested with BIOS Version 0906. Here's the info for each BIOS version:
Quote:
Originally Posted by Asus 
P9X79 Deluxe 0906 BIOS
1. Enhance PCIe 3.0 Support Capability.
2. Enhance DRAM Compatibility.
3. Enhance CPU OC capability.
4. Enable VT-d support for VT-d enabled processor.
5. Speed up S3 resume time

P9X79 DELUXE BIOS 1009
1. Improve system stability.
2.Improve memory compatibility.
3..Enhance compatibility with some USB devices.
4.Fix PCIEx16 VGA card HD 7970 cannot be detected when the temperature of VGA less than -40.

P9X79 DELUXE BIOS 1103
1.Improve Improve system stability.
2.Enhance compatibility with some USB devices.

Processor: Intel Core i7-3820 | Motherboard: Asus P9X79 Deluxe | Case: Cooler Master HAF-X | Fan: Noctua NH-D14 SE2011 | RAM: G.Skill Ripjaws Z DDR3 1600 16GB 4x4GB CL7 | HD: Samsung 830 SSD 512 GB | PSU: Seasonic Platinum 860W | Graphics: PowerColor HD 7950 PCS+ 3 GB
BuildBuildBuild is offline  
post #6 of 22 (permalink) Old 04-28-2012, 07:55 AM - Thread Starter
New to Overclock.net
 
BuildBuildBuild's Avatar
 
Join Date: Mar 2012
Posts: 28
Rep: 1 (Unique: 1)
So I still had the original P9X79 Deluxe Motherboard (Motherboard A) and decided to compare it to the P9X79 Deluxe I exchanged it for (Motherboard B). That would give me a good point of reference since they are the exact same Motherboard.

Well, here's where things get interesting...

I used the EXACT same settings for both Motherboards (Loaded Optimized Defaults, set CPU Strap to 125, set RAM manually to 1333 Mhz with Auto Timings, set Core Voltage manually to 1.37, all else left on default AUTO):

450

450


The original Motherboard (Motherboard A) passed Prime95 in over 8 hours:

362


The newer Motherboard (Motherboard B) failed Prime95 in under 3 hours:

362


You would think Motherboard B is faulty since it failed where Motherboard A passed, right?

Well, not so fast! If you look at the screenshots closely, you will notice that the Core Voltage in Motherboard A ranged from 1.38v to 1.41v (remember, it was set manually to 1.37), yet the Core Voltage in Motherboard B ranged from 1.37v to 1.39v.

So it would seem that the only reason Motherboard A passed Prime95 is because it gave the CPU a lot more juice. In other words, it seems like it "cheated"!

In fact, in previous testing, Motherboard B had passed Prime95 with a Core Voltage of 1.38v which happened to give the CPU the EXACT same range (1.38 - 1.41) Motherboard A gave it at 1.37v.

363

QUESTIONS:

1) Is it normal for a Motherboard to provide a Core Voltage from a minimum of 1.38 to a maximum of 1.41 when it is manually set to 1.37?
2) How can two Motherboards of the exact same brand and model perform so differently?
3) Which of the 2 Motherboards should I keep? (Or should I get a 3rd one because they're both stuffed?)


Processor: Intel Core i7-3820 | Motherboard: Asus P9X79 Deluxe | Case: Cooler Master HAF-X | Fan: Noctua NH-D14 SE2011 | RAM: G.Skill Ripjaws Z DDR3 1600 16GB 4x4GB CL7 | HD: Samsung 830 SSD 512 GB | PSU: Seasonic Platinum 860W | Graphics: PowerColor HD 7950 PCS+ 3 GB
BuildBuildBuild is offline  
post #7 of 22 (permalink) Old 04-28-2012, 08:00 AM
New to Overclock.net
 
DirektEffekt's Avatar
 
Join Date: Nov 2009
Location: Australia
Posts: 2,040
Rep: 142 (Unique: 96)
1) The voltage fluctuations are normal, it must have some LLC on.
2) Get them both returned, they're faulty and you're due an RMA, however as it sounds like you actually bought the second one, you may actually be stuck with two as I know many places don't give refunds. But definitely get an RMA. It's their job to make sure their boards work.

DirektEffekt is offline  
post #8 of 22 (permalink) Old 04-28-2012, 08:20 AM - Thread Starter
New to Overclock.net
 
BuildBuildBuild's Avatar
 
Join Date: Mar 2012
Posts: 28
Rep: 1 (Unique: 1)
Quote:
Originally Posted by DirektEffekt View Post

1) The voltage fluctuations are normal, it must have some LLC on.

Thanks, I had no idea such high voltage fluctuations were normal. The LLC was set to whatever the defaults are as I didn't touch that setting on either Motherboard. So if such high voltage fluctuations are normal, then it seems that Motherboard B is the faulty one since it failed where Motherboard A passed (even though it had a much higher voltage fluctuation).

Quote:
Originally Posted by DirektEffekt View Post

2) Get them both returned, they're faulty and you're due an RMA, however as it sounds like you actually bought the second one, you may actually be stuck with two as I know many places don't give refunds. But definitely get an RMA. It's their job to make sure their boards work.

Well, I exchanged the original Motherboard (Motherboard A) because it had a faulty CPUTIN temperature sensor (as you can see from the screenshot above). I hadn't even tried Overclocking it until I started having problems with the replacement (Motherboard B) and wanted to compare the two. Motherboard B was shipped to me free-of-charge by the online retailer and they gave me 30 days to return Motherboard A. Considering the problems with Motherboard B, I'm thinking of either keeping Motherboard A (and accepting the faulty temp sensor) or asking the retailer for yet another exchange (Motherboard C) and returning the first two. But if I get a third Motherboard, then my fear is that it will have a problem bigger than just a temperature sensor and then I'm back to square one.

What should I do? I had no idea these top-of-the-line parts could have so many problems.

Processor: Intel Core i7-3820 | Motherboard: Asus P9X79 Deluxe | Case: Cooler Master HAF-X | Fan: Noctua NH-D14 SE2011 | RAM: G.Skill Ripjaws Z DDR3 1600 16GB 4x4GB CL7 | HD: Samsung 830 SSD 512 GB | PSU: Seasonic Platinum 860W | Graphics: PowerColor HD 7950 PCS+ 3 GB
BuildBuildBuild is offline  
post #9 of 22 (permalink) Old 04-29-2012, 01:29 PM - Thread Starter
New to Overclock.net
 
BuildBuildBuild's Avatar
 
Join Date: Mar 2012
Posts: 28
Rep: 1 (Unique: 1)
Anyone?

Processor: Intel Core i7-3820 | Motherboard: Asus P9X79 Deluxe | Case: Cooler Master HAF-X | Fan: Noctua NH-D14 SE2011 | RAM: G.Skill Ripjaws Z DDR3 1600 16GB 4x4GB CL7 | HD: Samsung 830 SSD 512 GB | PSU: Seasonic Platinum 860W | Graphics: PowerColor HD 7950 PCS+ 3 GB
BuildBuildBuild is offline  
post #10 of 22 (permalink) Old 04-29-2012, 04:13 PM
New to Overclock.net
 
DirektEffekt's Avatar
 
Join Date: Nov 2009
Location: Australia
Posts: 2,040
Rep: 142 (Unique: 96)
The thing is, it doesn't seem that your board is faulty, if it passes with the same real voltage as A then I would say keep B and just go ny CPU-z volts!thumb.gif

DirektEffekt is offline  
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Overclock.net - An Overclocking Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off